This page exists to answer a question I see all the time: "Can I keep this turtle and that turtle together?" This question doesn't have a simple answer. It depends on the size of your tank, the size of your turtles, what species of turtles you have, how often you feed your turtles, etc. First, I will attempt to address the two major reasons why most of the experts say "no":

Reason #1: Aggression

If you put two turtles together in a tank, there's always a chance they won't get along. Agressive behavior can occur for 4 reasons:

1. Feeding: Some turtles see each other as a source of food.
2. Mating: Biting is a natural part of many turtles' mating rituals. This generally isn't a problem in the wild because the turtle being attacked can always run if she (or he) has had enough. In captivity however this behavior can lead to serious injury.
3. Meanness: Although they look cute, turtles can be mean sometimes. Perhaps they're being territorial, or maybe they're just sick of looking at each other, but sometimes turtles bite each other for no good reason.
4. Accidental Bites: Sometimes, turtles don't mean to bite each other. Generally this happens when two turtles start at opposite ends of the same piece of food. Inevitably, one turtle's foot gets in the way and gets bitten by mistake.

Reason #2: Pathogens

When you put two turtles together, any disease that one turtle has is spread to the other. Co-habitating of foreign species with desert tortoises and subsequent release of the tortoises was responsible for the introduction and spread of respiratory disease which is currently wiping out tortoise populations in California and Arizona.

So you still want to co-habitate your two turtles?

I don't want to discourage you from keeping your turtles together, but it's going to require a little more work from you. First, keep in mind that some species just aren't compatible. Consider the following when mixing turtles and turtle species:

1. Enclosure:

    When you are keeping several turtles together, you should choose a considerably larger tank (about 1.5 to 2 times what you would need to house one individual) to give the turtles plenty of room to avoid each other. The bigger the tank, the less likely you are to have problems. Make sure the tank has plenty of logs and rocks to break the turtles' lines of sight (so the turtles don't constantly see each other). If the turtles do decide to be aggressive, this will give the turtle being harassed a place to hide. Also, make sure the requirements of all species in the enclosure are met. For sliders, this means you'll need an adequate basking area and UV light (from sunlight or a full-spectrum basking light). Softshells require a shallow sandy area where they can bury completely yet still reach the water's surface. Small snappers, mud, and musk turtles require an easy climb or walk to the water's surface (they are poor swimmers).

2. Species and Size:

    Pretty much all baby turtles can be co-habitated with no problems, excluding perhaps snappers. After the turtles start to grow everything changes. Some species are much more agressive than others and will intimidate their tankmates, while some will run from any threat and thus never get enough to eat during feeding time. If you are keeping turtles agressive by nature, such as softshells or snappers, with other non-agressive species, the more agressive turtles should be the smaller turtles in the enclosure (agressive turtles are much less likely to bother a turtle twice their size). For reference, i have compiled a list of common turtle species and their general agressiveness on a scale of 1-5 (1=submissive, 5=very agressive). Please note this is only a general approximation, each turtle has a separate personality. 

    
                           Snapping turtles = 4-5
                        Softshelled turtles = 4-5
                               Musk turtles = 4
                                Mud turtles = 2-4
                          Red-Eared sliders = 3-4
                            Painted turtles = 3
                              Other sliders = 2-3
                                Map turtles = 1-3
                      Diamondback terrapins = 1-3
3. Geography:

    When co-habitating species, think about where they live in the wild. Do they occur together in nature? Do they occur within the same river system (and thus share immunities to any pathogens present in the river)? Do they live in similar regions/climates? Turtles that occur together in the wild are the best candidates for co-habitation because they are likely to be exposed (and therefore immune) to the same diseases. If one turtle is carrying a disease that you're unaware of, chances are you won't have a problem. On the other hand, turtles from different continents should NOT be co-habitated, bacteria naturally carried by one turtle could seriously affect the other.

4. Feeding:

    Take extreme care when feeding your co-habitated turtles, this is when most of your problems will occur. To minimize the risk of injuries (such as amputated toes) during feeding, feed turtles less food more often rather than more food less often. Also, if you feed fish, shrimp, or other treats, break them up so the turtles are less likely to fight over the same piece. If you want to eliminate this risk entirely, feed the turtles separately.





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