Adding a Second Reptile to Your Tank: Dos and Don’ts

By Laurie Hess, DVM, Diplomate ABVP (Avian Practice)

Like us, many animals like to hang out with friends. However, the same isn’t true of most reptiles. Reptiles do just fine solo and don’t require others in the same tank to thrive. In general, reptiles are better off housed individually.

Certain lizards (bearded dragons, anoles, geckos) and chelonians (turtles and tortoises) can live successfully together when set up properly in same-species tanks. Snakes, however, are best housed singly and generally should not be combined in one tank, even if they are of the same species.

If you are thinking about having more than one reptile in a tank, you can help ensure success with these six precautions.

First, be sure the tank is large enough to house more than one reptile. Each reptile, regardless of species, must have adequate space to exercise, hide, eat, bask, and generally escape the sight of the other reptile(s). The biggest mistake that reptile owners make is to get too small a tank to house multiple pets. Without enough space, pets in the same enclosure are more likely to fight over territory and get injured. In addition, larger tanks usually require additional heat and light sources, as well as more thermometers, to help ensure environmental conditions are kept constant.

If the tank is aquatic, additional rocks will be necessary to ensure that there is adequate dry land for more than one pet, and if the species is arboreal (tree-climbing), additional branches will be needed to ensure that everyone has a place to perch. In general, the larger the tank, the better.

In general, groups of same species females may be housed together with or without one male. However, only one male should be kept in the tank, as males tend to be more territorial than females and are more likely to fight. This is just a rule-of-thumb, as females can fight with each other as well, and individual males may torment females when they want to mate and are rebuffed. Therefore, regardless of gender combinations in a tank, when a new reptile is added and the social hierarchy is reconfigured, tank-mates need to be monitored closely for fighting.

If any aggressive behavior is noted, reptiles should be separated immediately before injury ensues.

Regardless of species, before a new reptile is introduced into an existing tank, it should be checked by a reptile-savvy veterinarian and quarantined for at least a month to ensure it doesn’t have infectious disease that can be transmitted to existing pets.

When stressed by a change in environment, a seemingly healthy reptile can break with disease (such as gastrointestinal parasites) when introduced into its new enclosure. This can result in illness and even death for the newly introduced reptile or for the existing pets. Therefore, housing the new introduction separately for at least a month while monitoring it for signs of sickness can help prevent tragic loss.

A second pet in a tank means twice as much fecal and urine production and twice as much wasted food. All this waste can build up in a tank quickly, leading to high ammonia levels, poor quality living conditions, and increased chance of infection spread. Thus, more than one pet in a tank means both more frequent spot cleaning of bedding and more frequent complete tank disinfection.

If the tank is aquatic, with more than one turtle in a larger tank, there will be more waste in the water, requiring a more powerful filter. All of this translates into more work for more than one pet. This will need to be taken into consideration before the final decision to add a new reptile.

Twice the number of pets means not only twice as big a tank, it also means twice as much bedding, food, and cage accessories (lights, heaters, rocks, plants, etc.). Therefore, not only is tank set-up more expensive, the daily care is as well.

Reptiles also need veterinary care, including annual check-ups and deworming. Thus, a reptile owner must consider whether he or she has the finances readily available to support medical care for more than one reptile over the long run, particularly given that many reptiles, depending on species, can live dozens of years or longer.

Reptiles of all kinds make great pets. When housed alone, they can be interactive, fun, and happy. Before you add a friend to your existing reptile’s tank or cage, be sure that the addition is appropriate, and take all precautions.

Even after you make the addition, monitor the animals’ interactions carefully to ensure that the transition is smooth, and remember that not all reptiles, even of the same species, want to share an enclosure. Like humans, some are more introverted than others. For some, living next door to each other rather than in the same house is preferable and better for everyone.