8. HEALTH CARE
5.1.1 What important points must I consider to house my caiman?
Appropriate housing is perhaps the most difficult part of keeping a crocodilian such as a caiman. You must consider several factors, including the size of the enclosure, how to divide it into land and water areas, heating both water and air, and how to best keep the water clean. Do not overlook the long-term cost of housing a crocodilian, not to mention the size of the area you will need. Be in no doubt, most crocodilians including caimans grow rapidly to large adult sizes. How are you going to deal with a 7 foot caiman which needs an enclosure several times its own body length?
When designing the enclosure, it must contain a water area and a land area. Crocodilians are semi-aquatic creatures. With their streamlined bodies and powerful tails, nearly all species are most at home in the water and this is where they will spend the majority of their time. However, they also require a land area to dry off and bask. You must ensure that the enclosure is spacious, both in terms of the amount of water and land. Within reason, you can't make the enclosure too large. Hatchlings only require a relatively small area, but this expands considerably as the animal grows. Also, other crocodilian species prefer different amounts of water and land in their habitat, so be prepared to experiment if necessary. Details of how large to make your enclosure, and how to set up the water and land areas are given later in this section.
You must also set up the right environment for your animal. Caimans require fairly warm temperatures to be maintained at all times, and both land and water heaters will be required. It is important to understand a reptile's thermoregulatory requirements as you design the enclosure. Unlike so-called "warm blooded" birds and mammals, reptiles such as caimans do not produce much body heat from metabolic processes (by burning stored energy) - they rely instead upon external sources of heat to warm up. A warm and toasty caiman is still warm blooded, but it didn't expend very much of its own energy reserves to become so. Reptiles have a range of temperatures that they like to reach, and these are called the preferred body temperatures (PBT). In many crocodilian species, the PBT ranges from around 29 to 34 degrees Celsius (84 to 93 degrees Fahrenheit). If a crocodilian's actual body temperature rises above this range, it will seek out a means of cooling down. If it falls below this range, it will usually make efforts to warm itself up again. So, your enclosure design needs to have areas where the caiman can either warm up or cool down depending on how warm it feels. In effect, you need to create what's called a "thermal gradient" - a range of temperatures from, say, 26 C (80 F) to 36 C (97 F), with enough space so that your caiman can move into a cooler or warmer area. In the wild, most crocodilians warm up by basking in direct sunlight on land, and then cool off by moving into a shaded area, or back into the water. Conversely, at night crocodilians stay warm in the water as temperatures on the land drop. Details on how to set up a thermal gradient and warm both land and water area are discussed later in this section.
5.1.2 How large does the enclosure need to be?
The answer to this question will depend upon the size of your animal, but you must also plan ahead and consider how quickly it will grow. Above all, your animal needs space. Space is important for several reasons. Your caiman may start off small as a hatchling, but growth is rapid. Despite what you might have heard, crocodilians do not stop growing when they reach the size of their enclosure, and their health and lifespan will be compromised if you don't enlarge it to keep up. Your caiman needs enough space to move around comfortably - to submerge and swim in the water, and walk around on the land. In addition to considering the amount of space your caiman requires, don't forget that every time you need to replace the enclosure with a bigger one, it's going to cost you money. Plan ahead - ensure that the enclosure will last for at least 12 months. Check the growth charts earlier in this document to find out how fast your animal could grow in a year or two.
But how much space does a certain sized animal actually need? As an absolute minimum, the enclosure width and depth should be 3 to 4 times the animal's total length, but larger sizes are preferable. In fact at least one country, Germany, will soon introduce quite specific requirements on the minimum size of an enclosure for a crocodilian. These apply to everyone in Germany, from private keepers to zoos, so they provide some guidelines to everyone. For a pair of crocodiles, minimum land area must be 3 times the largest animal's SVL (snout-vent length) wide and 4 times long. The minimum water area must be 4 times the largest animal's SVL wide and 5 times long, and minimum depth must be 0.3 times SVL. So, a pair of animals with a SVL of 1 metre (3.3 ft) - adult caiman size - would require a land area of 12 square metres (39.3 square feet) and a water area of 20 square metres (65.6 square feet) to a depth of 30 cm (12 inches). These German rules are intended for all species, although some species (like caimans) prefer a lot more water. Other countries, such as the US, may not have such minimum requirements (although check with your state's wildlife office), but these rules illustrate the kind of enclosure size you would ideally be looking at. More animals will require a larger space - under German rules for example, add 10% more land area and 20% more water area for each additional animal. Still think that crocodilians are easy to accommodate?
Plenty of space enables your crocodilian to walk or swim around comfortably, with the ability to bask and submerge if necessary. Space also makes it easier to set up a thermal gradient in the enclosure - with a range of temperatures that the animal can choose if it wants to warm or cool itself. Lack of space leads to inactivity, increased stress, and poor health.
5.1.3 What type of enclosure can I use for small crocodilians?
When small, hatchling and juvenile crocodilians can be kept in glass aquarium tanks. These tanks come in a variety of sizes, measured in gallons (US) or cubic dimensions (see Appendix IV). Ready-made tanks are available at most pet store outlets that deal in fish, and many places will construct a tank to order, with glass of appropriate thickness. You can, of course, build something yourself. Glass tanks are a simple solution because they're cheap, waterproof and easy to clean.
Some owners prefer to use glass or sealed wood terraria. Aquaria are open at the top, as they are designed to hold a lot of water. A terrarium normally has a covered top and a door on the side. Some owners feel that this is better for hatchlings crocodilians, as you're not picking the animal up from directly above (as a predator would) but rather from the side where it can see you. From this position, however, you are more likely to be bitten if the animal is being aggressive (and most of them are when you try and pick them up). A bite from a small caiman will do little more than break the skin, but for larger animals it is much safer for the handler to approach the animal from above (see 6.4 for handling tips).
Tim Weigmann elaborates on a typical terrarium design: "The terrarium I use for hatchlings is 1.2m x 0.6m x 0.6m high (3.9' x 2' x 2') and made of glass. The door is 20cm (8 inches) above the terrarium floor, so it's no problem to provide an adequate water depth. The whole water and land areas are sealed with silicon, which is easy to clean and provides a good grip for tiny croc feet. There are plenty of air holes around the sides, in the top and the doors, so ventilation is good and the air always smells fresh."
5.1.4 What type of enclosure can I use for larger crocodilians?
When your animal really starts to grow, whether it be a dwarf caiman or an American alligator, you'll eventually need to find a better solution than just an aquarium tank. There are many different ways of housing larger crocodilians, and whether you purchase something or build it, these ways are limited mostly by your imagination. However, they usually share certain elements in common, and you'll find a few ideas presented below.
You'll discover that it's hard to buy an aquarium tank or terrarium above a certain size (e.g. 2.0m x 1.0m x 1.0m is close to maximum) unless you have one built to order. Large glass aquaria are very heavy and require very thick glass - first to support the weight of water and land area, and second to resist breakage if your animal's heavy bony head crashes into it.
Tim Wiegmann prefers to use terraria: "I build a large terrarium out of wood and use glass only for the sliding front doors. The inside of the terrarium then gets two layers of fibreglass coating to make it waterproof, and ventilation grates are fitted into the roof and sides to ensure good airflow."
Large aquaria and terraria such as this normally need to be built in situ, or you'll never move it once you've built it!
Other materials can be used to build an enclosure for your animal, such as heavy plastic or fibreglass. These might not look aesthetically pleasing, but they are functionally sound if set up correctly.
Ragnar Lonn writes: "I now have a very large enclosure built from fibreglass (the same material most boats are made from - I had some previous experience building boats so I chose fibreglass because I knew how to work it). The new enclosure measures 2 x 1.2 x 1.3 metres (6'7" x 3'11" x 4'3") on the outside. The volume would be between 2500 and 3000 litres (600 to 800 US gallons). It holds somewhere in the range of 550 to 600 litres (140 to 150 US gallons) of water, has a waterfall, a tiny island, and a land area with a warm basking spot. This enclosure was not cheap to build - keeping crocodilians is a high cost hobby let me assure you. I expect to be able to house Burt, my spectacled caiman, in this enclosure until he reaches 1 to 1.2 metres in length. This will probably take a couple of years so I think I'm safe for the time being."
Be aware that fibreglass, while an ideal material for crocodile enclosures, can be quite dangerous to work with. Cutting fibreglass or working with loose fibres can produce a cloud of dart-like particles which can embed themselves in your skin, your eyes, or your lungs if you inhale them. Always wear protective clothing and a suitable mask when working with fibreglass until it has been painted with epoxy resin and hardened.
Another possibility is to use large, prefabricated tanks such as those used in aquaculture. These come in a variety of shapes and sizes, and can provide a good basic design upon which to build your setup. A table showing the dimensions of tanks available from Rubbermaid is presented in Appendix V. On the other hand, a small children's play pool is a much cheaper and still quite feasible option - although these are best used as pools within a larger land area. You can place ramps or logs around the pool to assist the caiman's attempts to climb in and out.
Prefabricated housing solutions only work up to a certain size, however, and beyond that you'll need to build something more extensive and permanent. Unless you have a very large house, this normally means you need to build the enclosure outside over a suitable area. In warmer climates, the animals can often be kept in these enclosures all year round, but in cooler climates they must be covered to retain the heat.
Tim Wiegmann has a lot of experience with keeping crocodilians warm outside: "Many crocodile keepers in Germany find that greenhouses are ideal for housing their crocs. These greenhouses are made from an aluminium frame which is covered with plexiglass. There are two types of plexiglass available - 16mm thick (two sheets sandwiching a single air chamber) and 32mm thick (three sheets sandwiching two air chambers). The plexiglass covering keeps the heat inside the greenhouse and, unlike glass, does not filter out UV-B light."
The outside area, whether in a warm or cool climate, needs to be enclosed somehow. A greenhouse is one solution, but if the area is open then a suitable fence needs to be constructed. The fence or wall surrounding the habitat needs to be strong and have substantial foundations - some crocodilian species are very good at digging, often creating burrows which can extend for several metres (and right under your fence into the neighbour's garden if you're not careful). Check with your local council or wildlife office about the suitability of your outside enclosure from a safety standpoint. In most countries it would be a requirement that the fence surrounding your crocodile enclosure meets a certain minimum safety standard and is secure from intruders or even stray pets. You don't want the neighbours knocking on your door asking if you're seen little Timmy lately.
The water and/or land area can be constructed from a strong plastic or concrete base. Tim Wiegmann elaborates: "Land and pond are can be made from concrete with heating pipes running through the concrete for colder climates. The whole concrete surface can then be coated with fibreglass which makes the enclosure 100 percent waterproof and easy to clean. There's also a kind of granulated rubber available which can be added to the fibreglass epoxy to make the surface much less slippery."
Some owners have resorted to keeping crocodilians in large enclosures in the basement or cellar of their house. However, this can cause serious problems as the heat and humidity from the enclosure rise into the house above, resulting in humidity damage. There are ways around the problem, such as ventilation (e.g. fans) which remove the humid air safely, but this can also result in a loss of heat and make the air too dry for the animals.
No matter what kind of enclosure you design and build, it's important to ensure that it can be cleaned easily, the water drained rapidly, and maintenance kept simple. There are an almost limitless number of ideas for building large enclosures.
5.1.5 How much water and land area does the caiman need?
All crocodilian species need both land and water, although most species spend more time in the water than on land. Most caiman owners find that their animal spends virtually all of its time in the water, and therefore they allocate at least 70 to 80 percent of the available space to water. The caiman still requires enough land space to emerge completely from the water - preferably at least twice the length of its body so it can walk around comfortably, and has easy access to a heated basking area and an unheated (or shaded) area. Dwarf caimans and dwarf crocodiles need much more land - perhaps half of the enclosure, although they will spend most of their time on land in a hide, which of course you need to provide. If not, they will try and dig their own.
In reality, the amount of time a caiman or other crocodilian spends in the water depends on several factors. If the water is warm enough for the caiman to reach a temperature within the range of its PBT then it will spend more time in the water - having little reason to come out onto the land to bask. However, if the water starts to fall below the lower end of the PBT, the caiman will emerge onto land in order to warm itself up under a suitable heat lamp from time to time. Another factor which influences how much time a caiman or other crocodilian spends in the water is stress. Most species of crocodilians feel most secure when they're in the water - not only can they move quickly and efficiently to escape, but they can submerge out of view. Caimans which do not feel safe in their enclosure will spend much more time in the water, even if it means not warming up enough. When you first enter the room containing your caiman, you might see it dash from land to water quickly and submerge, which is a typical escape behaviour. For younger caimans particularly, then, plenty of water is required for security and cover. The water must be deep enough for the caiman to submerge completely, and have enough area so that the caiman can walk around on the bottom and swim around comfortably.
Always use freshwater in a crocodilian enclosure. Although some species are more tolerant of saline conditions (e.g. the aptly named "saltwater" crocodile), all species thrive in freshwater.
5.1.6 Do caimans only grow to the size of their enclosures?
No, this is a myth. Perhaps it originated through unscrupulous dealers looking for ways to convince potential owners to part with their cash, but regardless of its origin it is not true. All crocodilians grow to be very large animals compared to many other reptile species. Even dwarf caimans, at 4 feet long, are a fair sized animal to try and house properly. The idea that a caiman can be kept small if the cage is also kept small is a seriously flawed idea. Even in a small cage, a caiman will continue to grow until its movement is eventually hindered. Continued growth will result in deformed limbs, snout and tail as the body tries to increase in size naturally. This is extremely cruel and results in a stunted and unhealthy caiman with a seriously compromised lifespan. The caiman must be provided with enough space for comfortable movement on both land and in water, or you should perhaps consider a stuffed crocodile toy instead.
5.1.7 Can caimans escape from enclosures easily?
Caimans certainly are capable of escaping from their enclosure if the opportunity is there. It is important to make sure the tank is tall enough to prevent escape - most crocodilians can climb and jump short distances, and if they can get out, they will certainly try. A secure lid, well ventilated of course, will help to keep your caiman from exploring the rest of your house uninvited. Ensure that any furnishings, such as logs, do not provide a convenient staircase for your animal. Dwarf crocodiles are excellent climbers and will treat sloping logs as an open invite to go exploring.
Larger animals can also escape from poorly designed enclosures. Big crocodilians are very strong animals quite capable of destroying weak fixtures and partitions. Some species, such as dwarf caimans, dwarf crocodiles and American alligators are adept at digging burrows, and can easily dig under a fence or wall if the foundations are not deep enough.
5.1.8 What furnishings need to go into an enclosure?
As a general rule, the enclosure will be easier for you to clean, and safer for your animal if you keep furnishings and decorations to a minimum. Furnishings can be defined as functional items such as gravel, stones, rocks and logs. Decorations, however, are non-essential items such as plants and other objects which might look aesthetically pleasing, but which are easily destroyed by the occupant and make cleaning more difficult. Whether you're using furnishings or decorations, ensure that they are very secure, so that your animal cannot knock them over and either break something or injure itself. Damaged fixtures should be removed or replaced as soon as possible.
Furnishings such as gravel and rocks can be used to create the land area. These should be tightly packed and secured into place. Eventually, however, detritus will work its way in between the rocks and gravel, so you'll need to be able to remove them occasionally for cleaning. Specific areas of larger enclosures can easily be covered with substrate to create banks and beaches if required. Both furnishings and decorations can be used to create shelter. Hatchlings in particular appreciate shelter (a covered area) around the water's edge, and species such as dwarf caimans and dwarf crocodiles demand a hide or burrow on the land.
However, never compromise the animal's living space in order to make it look a bit prettier. If it doesn't directly contribute to the animal's enclosure, and it takes up space or impairs your ability to clean properly, then remove it. Much larger enclosures can be made to look more naturalistic if required, with due consideration of the animal's natural habitat. Such set-ups require considerably more maintenance to keep them looking good.
The other important components of a set-up are heaters and water filters, and these are discussed in the following sections.
5.2.1 What temperature should their environment be?
Crocodilians are generally tropical or semi-tropical species, and so are used to warm temperatures and moderate to high humidity. Although some species are more tolerant of cooler temperatures (e.g. American and Chinese alligators), optimum temperature ranges generally overlap in all species. Nearly all species have a preferred body temperature of between 29 and 34 C (84 to 93 F), so naturally their environment must also contain these temperatures. Remember it's the body temperature which is important here, and ideally most species try and get their internal body temperature to around 30 or 31 C (86 or 88 F). Air temperatures can reach around 36 C (97F) during the day as long as the animal has an area to cool off when its internal temperature starts to get a little too warm. At night, temperatures should be lower to help simulate a natural day/night cycle, and can drop to around 20 C (68 F) as long as water temperatures are warm. Water temperature can be maintained at a fairly constant temperature. Around 27 to 31 C (81 to 88 F) is a good temperature range to aim for, although this can be slightly warmer if desired. Caimans and other crocodilians are fairly tolerant of short-term fluctuations in temperature, although it is more important to ensure that the animal does not overheat. Temperatures above 40 C (104 F) should be avoided.
Cooler temperatures can be tolerated for longer, but animals kept at temperatures below their PBT for long periods of time will not eat as well, will not grow as quickly, nor be as healthy. Alligators have been recorded to stop eating altogether when internal body temperature drops below 22 C (72 F). The problem with temperatures below the animal's PBT is it compromises the immune system and makes the animal more susceptible to stress and illness through bacterial or fungal disease. If you choose to maintain your crocodilian at the warmer end of the PBT, it will generally eat more and grow more quickly. It will also be healthier, and the chances of it dying as a hatchling with be much lower. Many crocodile farms, interested in maximising growth and ensuring a high rate of survival, keep their animals at constant, warm temperatures (31 to 32 C, or 88 to 90 F). In a private collection, however, thermoregulation is an important part of the daily routine, and the ability to choose the PBT should be offered to the animal.
Crocodilians found in more temperate climates (e.g. American and Chinese alligators) tend to have a slightly lower PBT, although the temperatures described above are more than suitable for both of these species.
5.2.2 How do I regulate water temperature?
Submersible aquarium heaters are the usual method of heating the water in smaller to medium-sized enclosures. These heaters come with different wattages, and it's suggested that you use around 1 watt of power to heat 1 litre of water - therefore a 300 watt heater should heat 300 litres of water satisfactorily. Less powerful heaters can be used, but will take longer to heat the water. All heaters should be controlled with a thermostat to prevent the water from overheating. Before you place any animal into the water, test the setup by leaving heaters on for several hours. If it's too warm, use a thermostat to reduce the power. If it's too cold, however, you may need additional heaters.
It is highly recommended that you plug all heaters into a ground-fault circuit interrupter (GFCI), and it is a legal requirement in the US in situations which require it (such as around crocodilian pools which use electrical heaters). A GFCI (which is not the same as a simple circuit breaker) is designed to save lives by interrupting electricity flow if you act as a conductor between an energised surface (e.g. electrified water) and ground. It usually takes considerably less than 100 milliamps to kill a human, so do not take the risk around water and electricity.
It can also be dangerous using submersible heaters inside the enclosure. They can be easily broken or bitten by the caiman, which will be electrocuted. There are several solutions to this problem, one of which is to protect the heating element in some way - for example, it could be hidden under an inverted and secured ceramic pot, or protected under a layer of securely fastened pieces of slate or shale.
Billy Heinbuch writes: "I have 2 x 300 watt aquarium heaters on the bottom of my caiman pond (the pond is 125 gallons, so adjust the number of wattage of heaters for different pond capacities), then on either side of the heaters I have pieces of slate slightly thicker than the diameter of the heaters. On top of the slates I have one big piece of slate which completely covers and protects the heaters. The wires are protected by rocks and artificial plants. The caiman never bothers them. This setup also allows the slate to warm which gives a greater surface area to warm the water."
Perhaps the best solution for smaller bodies of water is to look for a filter which also heats the water. Eheim manufacture such a "thermofilter" - a special pump & filter which includes a heating element to warm the water as it passes through, and a thermostat to modulate the water temperature. You can create a similar effect yourself with a normal filter by using your own heater outside the enclosure and then pumping in the warmed water. This is much safer than placing the heater inside the enclosure where it could be damaged.
John White writes: "I've placed my external water heater (aquarium heater or 9V DC ceramic water heater) and an aquarium pump (a Fluval model 403, canister filter, with the built-in pump at the top) in a 5 gallon bucket. Fill the bucket with water and you have a relatively safe heat exchanger. Because the Fluval canister filter is watertight there's no water exchange between "bucket water" and canister filter/enclosure water."
The only problem with the above solution, John points out, is that the water in the bucket can evaporate over time. This will break the ceramic heater if it dries out. You can prevent this by topping up the water occasionally or covering the bucket to minimise water evaporation. Regular checks on the equipment should be mandatory in any case. It should also be pointed out that usually only the canister part of the filter must be submerged unless the filter is designed for total submersion. Water and electricity don't mix, so check your filter type carefully before use.
Of course, water temperature will also be influenced by room temperature, so a warm room will eventually result in warm water once it's equilibrated. You may also place the heating element underneath the enclosure, such as a heating pad for small aquaria or terraria. For much larger enclosures, heating pipes can be set in the floor and connected to a suitable heating system (e.g. a house system such as a boiler or immersion heater).
5.2.3 How do I regulate air temperature?
Clearly the air temperature of the enclosure will be based around the temperature of the room in which it is housed. A cold room will require a greater degree of heating in the enclosure to maintain adequate air temperatures. At least one basking area is required in the enclosure, shining down onto one section of the land area. If your caiman needs to warm up by basking, it must be able to sit underneath the heater and reach a comfortable temperature without overheating too quickly. Therefore, the area beneath the heater must not be too hot. Use a good thermostat with your heater so that you can control the temperature more accurately, and increase or decrease it as required if the ambient temperature changes (or use a rheostat). It goes without saying that an accurate thermometer is invaluable to ensure your caiman's safety. Do not measure temperature on the ground under the heater, but rather measure it several inches above ground level, as this will be the level of the caiman's head or back as it sits under the heating element. The temperatures to aim for tend towards the higher end of the caiman's range of PBTs. See section 5.2.1 for more details.
Incandescent bulbs are commonly used as heating elements. They come in a range of wattages, so the right level of heat for the enclosure size can usually be found and then stepped down with a thermostat as required. This can only be determined through experimentation, preferably before the enclosure is occupied. Other heat sources especially suitable for larger enclosures include ceramic heat emitters (CHEs). These are available up to 150 watts in the US and 250 watts in Europe, and are an excellent alternative to incandescent heaters. Higher wattages will require a ceramic lamp holder, as the lamps become very hot indeed. Ensure that the caiman cannot reach the heater, or serious burns will result. One advantage of a ceramic heat emitter is that it can be used, perhaps at a lower capacity, at night without emitting light that would otherwise disrupt the caiman's circadian (day/night) cycle. Caimans are active at night as well as during the day but they do not require a night light - although feel free to use a dim blue or red light if you like. If you do use an incandescent light as a heat source, remember that the temperature will drop considerably at night when you turn it off. This is where CHEs come into their own. Other heating solutions also exist, and a glance in a specialist reptile store will reveal other possibilities.
It is important that the land area is large enough so that the caiman can emerge from the water into an area outside the basking spot, if desired.
5.3.1 What lighting does a caiman need?
Caimans require a day-night period in order to remain healthy, so lights should only be switched on for around 11 to 13 hours a day - about the day-length they would receive in their natural habitat. Some owners feel that it is beneficial to provide a night-light that simulates moonlight.
Day light can be provided using incandescent bulbs or fluorescent tubes, or simply natural light if the day-length is long enough. Dim light at night can be provided with coloured incandescent bulbs, or natural moonlight when it's available.
5.3.2 What about UV light?
In the wild, sunlight would also include ultraviolet wavelengths such as UV-A, UV-B and UV-C. These are not emitted by incandescent lights, so it is a good idea to consider at least a fluorescent light that emits both UV-A and UV-B wavelengths. Not everyone considers that these "full spectrum" lights are essential for all crocodilians (many are active primarily at night), but there is some evidence to support the idea that they are beneficial, especially when compared with crocodilians kept in total darkness or under artificial light. UV-B is important in the synthesis of vitamin D3, although caimans derive substantial vitamin D3 from many of their prey items which are part of a varied diet. The importance of UV-A is unknown, but there is a lot of circumstantial evidence that it does have a positive effect upon reptiles (e.g. increased resistance to disease, increased activity). Ultraviolet wavelengths are also thought to be important for skin hygiene, killing bacteria and algae which would otherwise grow in the damp environment.
Some species of crocodilians, such as the dwarf caimans (Paleosuchus) and the dwarf crocodile (Osteolaemus) often spend considerable amounts of their daytime hidden in burrows or under dense vegetation in the wild. Therefore, they are probably getting far less sun than other crocodilian species even in natural conditions and it seems unlikely that they would benefit from much UV-A or UV-B light in captivity. However, there is still very little known about the importance of D3 synthesis in crocodilians.
5.4.1 What's the best way to keep the enclosure clean?
Keeping the enclosure clean is an essential part of your caiman's health. There is no doubt that dirty water and an unclean enclosure can be one of the biggest causes of problems and disease which may affect your animal. Daily maintenance is straightforward - ensure that any uneaten food is removed from the enclosure as soon as possible, and faeces should be cleaned up immediately. The biggest cause of a dirty tank, apart from faeces, is caused by your caiman's feeding habits (see section 5.4.2). Using small, bite-sized pieces will make your caiman a tidier eater, with less spillage to clean up. However, cleaning the water every time it becomes dirty is a time-consuming task, and so a filtration system is normally used to maintain its cleanliness. Many owners use a filter/pump combination such as a Fluval or Eheim system as their basic filter, and this comes in various sizes depending on your requirements. These are measured by their capacity to pump a volume of water in an hour, so an Eheim 440 will pump 440 litres an hour. The use of various filtration media will help to remove both small and large particles of detritus.
Billy Heinbuch writes: "When my caimans were small enough for an aquarium I used a Fluval 403. This was good for up to 100 US gallons. The reason for this choice was that it provides excellent mechanical filtration but also provides chemical and biological filtration."
Aquarium gravel cleaners may be used to remove sediment that has settled within the gravel, and an under gravel filter can be a useful tool. Just because the water looks clean, however, does not mean that it isn't contaminated. Unless you replace the water frequently, it is advisable to use a bacterial system to break down harmful chemicals such as ammonia, which could otherwise build up to toxic levels within the water. In such systems, you need a large surface area for the bacteria to grow upon - such as a plate drilled with holes, or pebbles filled with holes. The water needs to pass through these holes, or the bacteria won't come into contact with the ammonia in the water. Within the nitrogen cycle, bacteria such as nitrosomonas and nitrosococcus break down ammonia into nitrites, and then further (e.g. using nitrobacter) into less harmful nitrates. This is an aerobic system, which means it involves oxygen. Therefore, it's important to use an air pump and air stone to oxygenate the water containing the bacteria. Further anaerobic processes (without oxygen) may break nitrates down into nitrogen gas. As you'll be using a freshwater system, ensure that the bacteria you're using are suited to a low saline environment. Bacterial systems are commonly used in aquaculture, so check your local aquarium for availability.
Billy Heinbuch provides an example: "Another filter system I use in aquariums along with the Fluval is an under gravel filter. This is basically a plate full of small holes kept under the gravel. Two power-heads force water down through the gravel where colonies of bacteria [within the plates] break down harmful ammonia. The power-heads also keep the water circulating which allows suspended particles to be picked up by the Fluval."
Not everyone considers bacterial systems to be necessary for crocodilians. Such systems are normally employed when keeping fish because the water is not replaced as frequently. Therefore ammonia can begin to build up in the water, and soon reach toxic levels if not removed. Many crocodilian owners feel that by replacing the water totally every few days eliminates the need for bacterial colonies to deal with ammonia. You can buy testing kits to measure the level of ammonia and nitrites in the water, so you can determine whether using bacterial filtration is necessary for your setup. Consider also that the expense of replacing water may be considerable in places where water is rationed or charged at higher rates during periods of drought.
Ragnar Lonn provides information on his setup: "I use small ceramic pebbles with holes in them as the first filtration medium. They catch the major debris and are also a good place for the bacteria to grow which break down ammonia. Also, rocks at the bottom of the water area sit on an aluminium grating. Debris falling through the rocks also falls through the grating and settles on the bottom where the water outlet is. Then I can just turn a valve, empty a gallon or two of water, and remove most of the settled debris. This doesn't work too well unless the bottom is sloped towards the outlet. For the finer particles I use common filter media, and then charcoal."
For larger enclosures, you will use a much greater amount of water. This may require a slightly different approach compared with filtering a small amount of water in an aquarium.
Billy Heinbuch says: "The enclosure I built had a 125 US gallon pond for the water area. This is a pond made out of black plastic and intended to be put in the ground outdoors. What I did was to cut a hole in the bottom of the pond and install a drain. Next, using a 3.5" PVC pipe I built a pre-filter and connected it to the drain using a 1" PVC pipe. The pre-filter contained pieces of filter sponge and ceramic filter media to catch large debris. After the pre-filter I ran 1" pipe to my pump. From the pump the water is sent to a pond filter. This is basically a small barrel with a return built into the side. The water is pumped into the top of the barrel and falls through the filter media and then runs back into the enclosure. I use larger PVC 1.5" and 1.75" for the return to the enclosure so there is less chance of the water being restricted and backing up the filter and back out the top of the barrel."
Another consideration is the build-up of a surface film of protein. Protein skimmers can be set up to "skim" off this top layer, although normally in a freshwater set-up they're unnecessary. If such a film develops, the easiest way to deal with it may simply be to remove it using a bucket.
The aquaculture industry spends millions of dollars on the problem of filtering water for the health of farmed animals, so the information presented here can barely scratch the surface of what is possible. However, for most caiman owners these guidelines should be sufficient. No matter what type of filtration system you use, however, frequent water changes (e.g. every 1 to 2 weeks) are still a necessity. Water can be changed by siphoning / draining it out, or as part of a larger clean of the entire enclosure.
5.4.2 How often should I clean the enclosure?
This depends on how efficient your filtration system is and how well you keep the enclosure clean on a daily basis. For small enclosures containing hatchlings, replacing the water daily is an easy task which is preferred by some owners. Larger enclosures can also be set up so that water is drained daily and replaced, although this is not necessary in systems which employ mechanical and biological filtration. Regardless of the filtration system you use, however, the water and enclosure must be cleaned periodically - usually every week or two. This means removing all furnishings and scrubbing down and disinfecting all surfaces. When you use disinfectant, ensure that it is dilute and that it is completely rinsed away before replacing the water. Cleaning is something which needs to be adapted to your particular setup and circumstance, especially for larger enclosures where removing all furnishings may not be practical. To disinfect, an antibacterial solution such as chlorohexadine (Nolvasan) may be used. Dilute the solution 1:10 with water before use, wash and soak the area for up to 30 minutes, and then rinse thoroughly with clean water. Household bleach (5.25% sodium hypochlorite) may be used with caution - 1 part bleach to 30 parts water (1/2 cup bleach to 1 gallon water). Again, wash off thoroughly with copious amounts of water after soaking for half an hour.
Many owners keep goldfish in their enclosure's water. These not only provide a convenient source of food for the caiman (see 5.1.2), but they also act as a water quality 'barometer'. If the fish start to develop 'fin rot' (where the fins start to turn black) then the water quality is becoming very poor. In addition, if the fish die soon after you've cleaned the water area and replaced the fish, then you didn't rinse the area well enough after cleaning. In both cases, replace the water immediately before your caiman also starts to suffer.
5.4.3 Can I clean the enclosure without handling the caiman?
In smaller enclosures, the animal may be removed and placed in a temporary holding tank. Some owners prefer to try and clean around their animal, as it often gets used to such disturbance and ignores the cleaner. However, if you're going to use disinfectant, it's very wise to remove the animal. Fumes may linger for several minutes even after a thorough rinsing. In larger enclosures, removing the animal each time you want to clean may be impractical. The crocodilian may or may not get used to the chore of having its enclosure cleaned. Again, you need to assess the situation and determine whether you can clean in a practical manner when the animal is present.
5.5 Are there any tips to keep the enclosure safe?
Keeping the enclosure safe for your crocodilian is often a matter of common sense. Here are some things to bear in mind. Crocodilians will often try to rearrange the furnishing, so ensure that anything heavy is secure and cannot injure the caiman or break anything if it topples over. Ensure that the glass is thick enough so that it doesn't break if the animal strikes it hard with its jaws (e.g. trying to attack something on the other side).
Ragnar Lonn says: "My caiman once tried to attack a fly that had entered its enclosure and was buzzing around close to the lamps like flies often do. The caiman jumped and hit the lamp with a loud clatter. Fortunately, the lamp didn't break. Now I've made the distance to the lamps from the water / ground level greater so it hopefully won't be able to reach them by jumping. Another thing to consider is the aforementioned fact that caimans often rearrange decorations inside their enclosure - this caused me to stop keeping moderately large stones in the water area of my enclosure. I was afraid the caiman would bump the stones against the glass and crack or shatter it. All the large decorations in the water area are wooden branches now."
Keeping a heat lamp further from the water also prevents water splashing onto the hot glass of the bulb and causing it to shatter. Caimans have also died by biting their water heaters and electrocuting themselves, so ensure that these are either protected or outside the enclosure (see 5.2.2).