There are several species of freshwater turtle that are commonly kept as pets, originating in several countries throughout the World. In British terminology, they are freshwater turtles, but they may all be incorrectly referred to as terrapins. (Terrapin is a native American word referring only to a few types of American freshwater turtle, which could also cope with brackish water, and were considered edible.) If you are looking for "turtles" that live on land, they are called "tortoises" or "American box turtles" (which are not covered by this guide).
Turtles can be very entertaining pet reptiles, becoming quite interactive, and learning to greet their owners, especially in response to the offer of food. All live primarily in fresh water, and keeping them is similar to keeping tropical fish, quite unlike the closely related tortoises, though they will also make use of land. They are diurnal (awake during the day). Turtles can often run quite fast, similar to their owner's running speed, and are able to climb a great deal of obstacles, including rocky outcrops, fences and stone walls. They rarely bite humans (except when investigating fingers to see if they are food), but if they do, their beak can produce a painful pinch. In all cases, their shells are just a few cm long when they hatch, and they are normally sold soon after hatching.
These turtles are from tropical or specialist climates, and are not adapted to the British climate. For the whole of their lives, they need to be provided with an indoor enclosure that can replicate the important parts of their natural environment. There are no pet turtles available that can live in garden ponds year-round; the turtles that can cope with the British climate (some of which are called terrapins) are now classed as invasive and legally banned from sale or changes in ownership.
These turtles all take around 5 years to reach their adult size, and can live for between 20 years for small species, and 40 years for larger species. Turtles will not stop growing just because they outgrow their enclosure, and owners need to be prepared to house the adult-sized turtle for its long life.
Musk turtles are from the eastern side of North America, and normally have a shell about 10 cm (4 inches) long. They are a bottom-feeding type of turtle, which normally have ridge along the middle of their shell as youngsters, and a smooth shell as adults.
Reeves' turtles are from eastern Asia, and normally have a shell about 12 cm (5 inches) long. They are active swimmers, with a distinctive long tail and shell ridges.
Map turtles are from the eastern side of North America, and normally have a shell about 15 cm (6 inches) long for males and 18 cm (7 inches) long for females. They are active swimmers, with many species having a distinctive ridge along the middle of their shell.
Chinese stripe-necked turtles are becoming a popular replacement for the various sliders. They normally have a shell between 15 cm (6 inches) and 20 cm (8 inches) long, and also have a long tail. They are active swimmers.
Painted turtles are from the middle and eastern edge of North America, and have a shell size ranging between 10 cm (4 inches) and 25 cm (10 inches) long. Females are larger than males. They are active swimmers, with life span records of over 50 years.
African mud turtles range between 15 cm (6 inches) and 28 cm (11 inches) in shell length, with distinctive sideways-swinging necks (a type of side-necked turtle), a quirky smile, and a hinged plastron in many species. They are bottom walkers that prefer not to actively swim, even though they are capable of it.
Sliders and cooters include many species that were previously popular, with a shell normally about 20 cm (8 inches) for male sliders, and up to 30 cm (12 inches) for female sliders. Cooters can be several cm (a few inches) larger. These are the turtles that may be correctly called terrapins, and can cope with slightly salty (brackish) conditions as well as fresh water. Red-eared sliders, yellow-bellied sliders and Cumberland sliders are now legally banned from sale or changes in ownership within Europe, though their existing owners may continue to keep them as pets. Hieroglyphic turtles and other cooters are still allowed to be sold as pets, but as they are often confused with yellow-bellied sliders, very few are now available for sale. All of these attractive turtles are active swimmers, and require relatively large enclosures, making them quite undesirable for many households as adults, in spite of seeming quite small and beautiful as youngsters. The growth rate can be surprisingly rapid.
The information here may be applied to a few other similar species of turtle as well, by adapting the approach used for the most appropriate turtle species.
For young turtles, a glass aquarium is normally best. For larger species, a plastic turtle tub is often preferred for adults, with most designs having a soil-filled land/nesting area and a larger water area. With glass aquariums, young turtles often prefer to have the back and sides of the aquarium covered with an aquarium background, so that the turtles can feel that they are sheltered from view, which reduces stress. It is normally best to use an open-topped aquarium - one without a lid - to prevent condensation from covering the glass, and to allow more control over the warm and cooler areas. Turtle aquariums are usually wider (front-to-back) than fish aquariums, as turtles cannot turn corners very well and may hit the walls if the aquarium is too narrow. Musk turtles are normally small enough as adults to cope with fish aquariums.
Young turtles should be kept in smaller enclosures so that they feel more secure. An aquarium 60 cm x 45 cm (24 inches x 18 inches) will normally serve a young turtle of any of these species for at least their first few years. The larger species or more active swimmers will need more space as they mature, perhaps 100 cm x 75 cm (40 inches x 30 inches) of water space for fairly large and active ones. Especially large painted turtles, sliders and cooters may need 150 cm x 75 cm (60 inches x 30 inches) of water space. If turtles are kept together, additional water and land space is needed, but the initial aquarium size mentioned above would be enough for a pair of adult musk turtles, or 3-4 youngsters of any of these turtles.
Turtle aquariums are only partially filled with water, normally to about half-way. Turtles will climb out if they can reach from their land area to the top of the aquarium wall, so there must be an air gap of more than the length of the turtle's shell above the water. The water depth must be right for the type of turtle. Active swimmers such as the Reeves' turtle, map turtle, Chinese stripe-necked turtle, painted turtles, sliders and cooters need a water depth at least double the length of their shell. Bottom feeders such as the musk turtle need to be able to safely reach the bottom and back easily; a depth of no more than twice the length of their shell is normally good. Bottom walkers like the African mud turtles need large parts of the water to be shallow enough for them to stand on the bottom with their back legs, and lift their head above the water surface; only slightly more than the length of their shell.
When initially filling the aquarium with water, the water should be pre-mixed to the correct temperature in a bucket, and the correct amount of dechlorinator added. The correct amount of filter-start (bacteria to help the filter get started) should then be added, and the mixture thoroughly mixed. It can then be put into the aquarium, to the correct depth. Heaters and filters should not be switched on until after the water has been filled to the correct depth.
For most turtles, the floor of the aquarium does not need any substrate (bedding). Sand must always be avoided, as turtles may accidentally eat it, and it can cause internal blockages. For musk turtles, it is important to have pebbles on the floor that can catch their food, and allow them to forage for it. If a substrate is desired, dedicated turtle pebbles may be used for all of these turtles.
These turtles must have a land area large enough for them to rest on, which they can climb onto from the water. This is normally done using a floating dock which floats on the water surface, moving up and down with the water level in the aquarium. Alternatively, it may be done as a static surface (which requires water levels to be carefully maintained) or a ramp which descends into the water. The land area is placed directly beneath the basking lamp (if one is used) and the UVB lamp. The land area must have easy access to the water, as the turtle will want to run into the water when startled. They may fall off high land areas and hit any other ornaments that lie below.
For adult females, whether breeding or not, it is important to offer a nesting box filled with an inert soil for them to lay eggs in. Moist coconut fibre bedding is the best option. This can simply be a plastic tub placed on the land area, with a ramp up to it. The nesting box should be about twice as long as the turtle's shell length, twice as wide as the turtle's shell width, and as as tall as the turtle's shell length. The soil should fill the nesting box to about half way, so that the turtle can dig a deep enough nest to lay eggs without spreading the soil everywhere, and still be able to climb out. It helps to have a dark cover over most of the nesting box, so that the turtle feels secure when using it.
Like fish, turtles need a filter that can process the waste produced by the turtle and their food. Natural bacteria in the filter convert harmful waste chemicals into safer chemicals, and the filter sponges capture large pieces of waste. For smaller aquariums, an internal filter is normally used, which is placed partially or completely beneath the water inside the aquarium. For larger aquariums or turtle tubs, an external canister filter is normally used, with the filter placed in a cabinet beneath the aquarium, and pipes leading into the aquarium. The external filters are much more effective and require less cleaning. The flow rate must not produce fast currents in the aquarium, or poor swimmers such as the musk turtles and African mud turtles may struggle to reach their resting areas. The filter should normally be over-rated for the size of the aquarium, as turtles can produce more waste than similarly sized fish. Turtles are not as sensitive to the harmful waste chemicals as fish, since turtles do not use gills to breathe. The turtle may be placed into the aquarium on the day it is set up, and you do not normally need to wait for the bacteria to build up in the filter (for fish, this "cycling" process may take a month before the fish should be added to an aquarium).
At all times, an aquarium heater keeps the water heated to tropical temperatures, suitably powered for the amount of water in the aquarium. For all of these turtles, a water temperature of 24°C or 25°C is best. The African mud turtles can cope with water temperatures a few degrees higher (never more than 29°C), but this may cause shy turtles to stop basking, which can have detrimental health effects - a temperature of 24°C is recommended. Dedicated turtle water heaters often do not allow the temperature to be altered. If your heater is adjustable, use a thermometer to check the actual water temperature, and adjust the heater until the thermometer says that the water has reached the correct temperature; do not rely on the heater's temperature indicator, as they are often inaccurate. Heaters must have a plastic guard to prevent the turtle from touching the hot surface. The water heater is kept on during the day and night.
Apart from the musk turtles, all of these turtles will need a basking lamp. During the daytime, the lamp heats part of the land area to over 30 to 35°C (86 to 95°F), leaving the rest of the enclosure at water temperature. This is usually held in place using a clamp-lamp which is clamped to the wall of the aquarium. The turtle chooses to use the heated area when it wants. At night time, the temperature of the land area is allowed to drop quite low; a typical house should be warm enough.
Note that basking lamps, like most heaters, work by radiated heat, not by heating the air. Thermometers usually measure the air temperature, so will give a false reading. The important temperature is the one that will be reached by an object - the animal or something representing it - when it is placed near the heater for long enough to absorb the radiated heat (a number of hours). Infrared thermometers allow you to measure the temperature of the substrate, ornaments, and animal, rather than the temperature of the air. Wet substrates will appear to be colder than dry ones. Test dry surfaces when measuring temperatures.
Most of these turtles benefit from having a few plastic plants in the aquarium water, which they use for resting in and sheltering in, and which make them feel more secure. This is especially important with musk turtles, and with shy species such as the Reeves' turtle. Other decorative or hide ornaments may also be added, as long as the turtle cannot become wedged in them. Live plants should never be used, as the turtle will either quickly eat them or uproot them. Plastic plants may also be attached to the aquarium walls above the water, allowing young turtles to climb into them. Ensure that the turtles cannot use them to climb out.
The enclosure may be placed in almost any room, not in front of a radiator, and not in direct view of sunshine. At all times, the animal and enclosure must be kept away from smoke, fireplace and cooking fumes, aerosols, chemical/alcohol sprays, air fresheners, and any scented or fragranced products that are not safe for use with reptiles.
Turtles breathe from the surface air, and do not need any kind of aeration or air pumps in the water.
The basking lamp is a special spot lamp, designed to project its heat downwards and spread it the right amount for the turtle. It is best to buy a dedicated bulb; specialist turtle bulbs have thicker glass that is less likely to shatter if it is splashed by accident. It hangs downwards so that it points towards the land area. For a smaller aquarium, a 40 Watt basking lamp is normally sufficient, while larger tubs may need 100 Watts.
Turtles need vitamin D3, which they naturally obtain from UVB light. They require it in quite high levels, and they require a UVB bulb. It is essential equipment, and bone and shell problems are common with turtles that are kept without adequate UVB lighting. Normally the problems are not seen for several months, then the turtle suddenly deteriorates and dies, or becomes permanently disabled.
The UVB lamp must be replaced every 6, 9 or 12 months depending on the brand, even if it still appears to be functioning (human eyes cannot see when the UV output drops too far). Write the date on the bulb with a permanent marker to avoid forgetting. For most of these turtles, the UVB strength should be the medium strength normally used for forest-dwelling reptiles, sometimes labelled as "5%" to "7%". For African mud turtles, the UVB strength should be the stronger strength normally used for desert-dwelling reptiles, sometimes labelled as "10%" or "12%". Reptile Systems and Zoo Med lights are recommended. UVB is often provided using dedicated turtle UVB lamps which are clamped to the aquarium wall, but compact fluorescent UVB bulbs or UVB strip lamps with an appropriate power unit may be used instead. The UVB lamp should be mounted an appropriate distance from the turtle; about 20 cm (8 inches) for compact fluorescents and dedicated turtle UVB lamps, or 30 to 38 cm (12 to 15 inches) for T8 strip lamps. For most turtles, the UVB lamp must be placed so that it shines onto the land area. For musk turtles, the UVB lamp is placed so that it also shines onto a plastic plant that is in the water, as these turtles often prefer to remain resting at the water surface while collecting UVB. (Cheap fakes - household bulbs with their labels removed - have been found. Make sure you are buying a legitimate, branded bulb from a reputable retailer.)
For plastic turtle tubs, it is often easier to use a single mercury vapour "D3+Basking" bulb, which gives off both heat and UVB in the same bulb. This is usually held in place using a clamp-lamp or support arm above the tub.
Lighting patterns should match the sun, switching on in the morning and off in the evening, eg. 8:00 AM to 8:00 PM, with no difference between summer and winter day lengths. Both lights must switch off at night so that the turtle can experience a natural sunlight cycle.
For smaller aquariums, the water needs to be partially changed every fornight or so. For larger aquariums or when using external canister filters, this can be done less often, perhaps every few months. The glass may optionally be scraped with an algae scraper, to remove any visible algae. Multiple turtles and species with large appetites need the water changes to be done a little more frequently.
Stir up any debris on the aquarium floor, and syphon about a third to a half of the aquarium water into a bucket, trying to suck up as much of the debris as possible. Mix some clean tap water in a bucket, to the same temperature as the aquarium water. Add the right amount of dechlorinator for the amount of water. If you have some, add the right amount of filter-start for the amount of water, then pour the water into the aquarium, to reach the correct water depth. The turtle does not normally need to be removed from the aquarium during this process. If the water heater is likely to be exposed to the air during water changes, it should be turned off and allowed to cool for a few minutes before reducing the water level, then turned back on after the aquarium has been refilled. It is best to switch off the lighting and filter during water changes too.
The filter also needs to be cleaned about the same frequency, or whenever its flow rate has dropped. It is important not to kill the bacteria in the filter, so cleaning products and tap water should never be used. Put some of the aquarium water into a jug or bucket. Unplug the filter, remove it from the water, and remove the filter sponge from the filter. Place the sponge into the jug of water, and gently squeeze it a few times to clean the waste products out of it. Remove any debris from the filter using a scrubbing brush. Clean external filter pipes with a pipe-cleaning brush. If the filter has ceramic media for holding bacteria, keep them in some aquarium water while cleaning the rest of the filter. Reassemble the filter, place it back in the aquarium, and plug it in. Top up the water as above. It is best to clean the filter on a different week from when you change the water, to preserve more bacteria.
Whenever needed, surface skimmers may optionally remove surface debris, and battery-powered manual filters may optionally remove faeces or other debris to reduce the load on the main filter.
These turtles are happy to be kept either singularly or in groups of two or more, as long as the turtles are a similar size. For most turtles, groups may be same-sex or mixed-sex. In general, it is best not to mix species, although similarly sized species may be kept together if they are adapted to the same conditions. Unrelated species may sometimes cause each other to become ill due to their different immunities.
Sexing young turtles is not normally possible. In some turtle species, adult males may have longer claws on their front legs. In others, the tails may be a different shape. In most species, the shape of the plastron may be slightly different in adult turtles.
Owners legally must not allow the slider species to breed within Europe. Fertile eggs may be frozen within a day or two of laying in order to prevent them from developing into an embryo, and can then be thrown away. It is best not to keep sliders in mixed-sex groups, to avoid any possibility of fertile eggs being overlooked.
Turtles will eat or injure any fish or any other aquatic animals that they can catch. They should not normally be kept with fish.
Turtles get their exercise by swimming in their aquarium, and do not like to leave it. They should not be removed from the aquarium except for the purposes of cleaning or transporting. Turtles in general do not appreciate being held, and will normally try to run back into the water as soon as possible. Some may even produce unpleasant smells when held, particularly musk turtles. While some owners may like to see their turtle running around on the floor of the room, this is stressful for the turtle; it is trying to find its home. Although it may look fun in online videos, turtles also do not appreciate being placed in a shower - some may try to shake off the water, thinking that it is another turtle trying to mate with them.
None of these turtles should be housed in outdoor ponds. Although the sliders can often cope with the conditions (and many owners like to keep them this way), the owner is legally liable if the turtle manages to escape, and it is simply not worth the risk, as they are excellent escape artists.
If an owner chooses to house the turtle outside anyway, such as with cooters and painted turtles, it is best to do so only with adults and only during the hottest summer months, when the sun can provide sufficient UVB and heat. Alternatively, UVB and basking lamps can be mounted in a rain-proof covered area above the pond or land area, giving a few more months of pond usage. Miniature greenhouses made from UV transmitting glass or UV transmitting acrylic can allow the turtle to bask in the warmth while sheltering from the weather - care must be taken to provide enough ventillation to avoid overheating. Heated ponds can make the conditions more favourable.
If the turtle can cope with hibernation during the British winter (see below), the pond needs to be deep enough to avoid freezing all the way down (such as 120 cm - 4 feet - deep), with a layer of mud at the bottom to allow the turtle to bury in it, at least as deep as the length of the turtle's shell. Oxygenating plants help to create oxygen bubbles beneath any ice layers, but the turtle will often eat or kill the plants. Pond heaters can remove the need to hibernate, or prevent ice from forming for a small area of the pond surface.
Ponds can have areas with different depths, and plants on elevated platforms to provide shelter. The land area can either be floating logs or stacked rocks in the pond, or the land around the edge of the pond. The entire outdoor enclosure, both pond and land area, must have very secure and slippery tall walls that the turtle cannot possibly climb over. The walls need to be dug about 30 cm (1 foot) into the surrounding soil as well, so that the turtle cannot dig down and get under the wall, or a wire mesh can be installed below the turf to prevent digging. Netting over the entire enclosure stops predators, particularly herons, from eating turtles. Some owners like to have sacrificial fish in the same pond, so that herons will catch the fish instead of the turtle.
These turtles are adapted to their natural diet of various leafy weeds, algae, insects and other aquatic animals.
Young turtles need to be fed twice per day, with however much food they can eat within 5 minutes. Uneaten food should be removed with a fish net. Adult turtles normally need to be fed once per day. Chinese stripe-necked turtles only need to be fed once every two days as adults. African mud turtles only need to be fed once every two to three days as adults.
Turtles are normally fed a commercially prepared pelleted food, which contains the correct types of animals and plants, as well as essential calcium and minerals. There are various complete diets based around these pelleted foods. Live food such as worms, mealworms and bloodworms are offered perhaps a few times per week, to allow natural hunting. Frozen food blocks may also be used as a treat. African mud turtles need more insect or live food protein than the other turtles. The food is served wet, usually floating in the water.
Musk turtles need some of their food to sink to the bottom so that they can forage for it between the pebbles. African mud turtles sometimes enjoy this too. This sinking food needs to be left for longer than 5 minutes, so that the turtle can find it all.
Some owners prefer to mix their own foods from roast chicken, raw salmon, mealworms, various plants and nutritional supplements. However, this is not a natural diet for a turtle, and it is difficult to get the nutritional balance right.
Although some terrapins (the various sliders) and painted turtles can hibernate in order to endure the British winter, most turtle species cannot cope with cold temperatures, and should not be forced to hibernate during winter - their temperatures should be kept the same at all times of year. The African mud turtles may aestivate if their water becomes too hot and shallow in summer - this can cause feeding problems and possibly death from dehydration, and is not needed except when trying to increase breeding success (successful breeding is still possible without it). Do not attempt to hibernate (brumate) or aestivate your turtles. If done improperly or in species that cannot cope with it, the turtle will not survive.
Turtles occasionally shed their skin. The skin peels off in pieces from their head (particularly their neck), legs and tail area. They should be left to complete this on their own - owners can rip the new skin if they attempt to assist the turtle.
All except the African mud turtles will occasionally lose thin layers of the shell scutes, like a thin, transparent plastic film.
Turtles are generally healthy animals when cared for correctly, and rarely require veterinary care. Some of the more obvious signs of problems include:
Puffy eyes normally indicates that there are harmful chemicals in the water. This can be caused by failing to use a dechlorinator, or by changing the water or filter sponges too often, killing the bacteria in the filter. It can also be caused by failing to change the water for extremely long periods of time. Aquarium shops usually sell water testing kits which can be used to check the chlorine, ammonia, nitrite and nitrate levels, to see if any of them have risen too high, as well as testing the pH of the water to ensure it is not too acidic or basic (alkali). The testing kits are designed for more sensitive fish, but the same chemicals can cause problems for turtles if they are exposed to elevated levels for too long.
Fungus can normally be solved with aquarium treatments designed for fish (such as Protozin), or certain topical ointments designed for humans (such as Clotrimazole by Canesten). Dry-docking and salt baths can be extremely harmful for young turtles.
Female turtles may regularly lay fertile eggs if they live with males, or may sometimes lay infertile eggs even if they have never lived with a male. Before or after laying, care should be taken to ensure that they are receiving adequate calcium in their diet. If a female appears to be repeatedly digging and straining without laying, or becoming lethargic at a time when egg laying is expected, she may need to be checked for egg binding.
You may optionally weigh your turtle on a regular basis, or when you suspect it is ill. Dramatic weight loss (eg. 10% in 2 weeks) suggests that veterinary treatments are needed. Weigh after the turtle has pooped, to get its "empty weight".
Turtles may avoid food for significant periods, especially if preparing to lay eggs. Seek advice as needed.
African mud turtles should never lose layers of their shell.
Reptiles can be quite sensitive to non-reptile medications. Only use medications which can be safely used with reptiles, or which are prescribed by a vet. They are particularly sensitive to alcohol and solvents. Any use of treatments where alcohol is used as a solvent must be done in a well ventillated environment, not in the confined space of the animal's enclosure.
Quarantine is not needed with your first reptile. However, as you gain more reptiles, it becomes more important. The general idea is to keep newly acquired animals away from your existing animals for long enough that you can be sure they are not bringing in any illnesses which could harm the existing animals. This quarantine period could last around 2 to 4 weeks for a basic quarantine, or as much as 6 months for an ideal quarantine. If any existing animals become ill with a potentially communicable disease, they can also be immediately moved into quarantine to protect the other animals.
A basic quarantine would simply be to keep the animal in a separate enclosure from existing animals, even if they will end up sharing an enclosure later. A more advanced quarantine would be to keep the quarantine enclosure in a separate room, using cleaning tools that will never be used for the others. Disposable rubber gloves can be worn when touching the animal or any part of its enclosure, and thrown away after each use.
A quarantine enclosure would ideally be made of something that can be easily and completely disinfected, perhaps even steam cleaned, leaving nowhere for any diseases or parasites to hide in it. A plastic tub with no substrate normally serves this purpose very well. All ornaments should be similarly easy to clean and disinfect, and considered disposable, so that they can be thrown away if an occupant turns out to be carrying a communicable illness. Although animals in quarantine need to be monitored, all work with quarantined animals should take place after any other work has been done with non-quarantined animals, to avoid carrying illnesses back to the non-quarantined animals. If food is refused by a quarantined animal, the leftover food should not be offered to a non-quarantined animal.
If an animal (whether in quarantine or not) is to be put into an enclosure that was previously used by another animal, the enclosure and ornaments should be thoroughly cleaned and disinfected with a reptile-safe disinfectant first, and any substrate replaced. If the previous occupant died from a communicable disease, it is perhaps better to dispose of the old enclosure and ornaments, and purchase a new one. Although rare, some of the most serious parasites (such as cryptosporidium) can survive for 2 years in an empty enclosure, and cannot be killed by simple disinfectants.
Turtles can travel for many hours in a small, ventillated box, with damp tissue for bedding. The box should be placed on your lap in a car with the heating on if needed. They should not be heated from below with anything hot. Hot water bottles and electric heaters should be avoided. If they soil the box, replace the tissue.
There are few - if any - boarding services that can care for turtles. If the turtle is to be left for any length of time, automatic mechanical fish feeders may be used to dispense their usual food. They should be regularly checked to ensure that nothing has gone wrong with their enclosure.
This information relates only to the European Union and the United Kingdom. Other countries may have their own regulations.
Sanctuaries are increasingly unlikely to accept hand-ins, as they will struggle to rehome the turtles. It is likely that hand-ins will have to be destroyed. Turtles that have already been illegally released into the wild are increasingly likely to be captured and destroyed in order to protect native wildlife. Owners may optionally choose to have their pets destroyed by a vet, if they are no longer able to care for them, and cannot find a sanctuary willing to take them in.
This is only a quick summary. For the actual wording of the relevant laws, see the EU regulation 1143/2014 on Invasive Alien Species, the human readable version, or the information on UK legislation relating to the EU regulation.
This is just a quick guide to get you started. It is not intended to be a complete book, and cannot replace a well written book, or the advice of an expert. It is based on our own best knowledge at the time of writing, and advice may change over time as new techniques, technology, or medical advice becomes available. Owners are responsible for ensuring that their knowledge is kept up to date. This guide is based on the British Isles, but the basic principles may be applied to other areas too.