As opportunistic omnivores, painted turtles (Chrysemys picta) will not hesitate to snatch a passing fish, so only extremely quick, large or well-armored fish are likely to survive cohabitation.
Keeping your turtles well-fed and housing them with large fish with help reduce their piscivorus ways, but you can never ensure the fish will survive. Some individuals simply make better tank mates than others do, and housing fish with your painted turtles is a daily experiment.
Regardless of the size and species chosen, wise keepers avoid bonding with their fish and prepare themselves for abrupt changes in the tank’s food chain.
Quick and Agile Fish
While painted turtles are skilled swimmers, they rarely catch extremely quick and agile prey. Neon tetras (Paracheirodon innesi) are gorgeous additions for the tank, and they usually zip around the tank quick enough to avoid turtles. Neons prefer to hang out in large groups and require plants among which they can hide from predators.
Rosy barbs (Puntius conchonius) are another peppy species, who are often capable of living alongside turtles. Like neons, they do best when kept in groups comprised of at least five fish. As omnivores, rosy barbs will consume some of the organic debris your turtles create in the tank, but they also may nibble on the plants.
Painted turtles typically prey on relatively small fish, although they may readily feed upon injured or dead fish of any size. This is partially because large predatory fish, such as largemouth bass (Micropterus salmoides), feast on turtles when the opportunity arises, but it is also because trying to capture and consume a large fish may cause the turtle to suffer an injury.
Because fish take on a variety of shapes, it is difficult to generalize about the size necessary to confer safety. The fish should be at least as long as the turtle, preferably much longer.
Keeping relatively large fish with your turtles embraces these natural tendencies, but this increases the necessary tank size dramatically. If you are prepared to offer your pets a suitably large habitat, try to keep the turtles with peaceful species. While adult painted turtles find fishbowl-sized goldfish delicious and easy to catch, large goldfish or koi may thrive alongside your painted turtles. Oscars and other robust fish also stand a good chance of surviving alongside your turtles.
While they do not grow to especially large sizes, sunfish, such as bluegills (Lepomis macrochirus), have disc-shaped bodies, which affords them some protection from the turtles. Be sure to select a sunfish species suitable for the water temperature of your tank, and verify that it is legal to keep them as pets in your state.
Large armored suckerfish (Hypostomus plecostomus) are likely among the best choices for painted turtle tank mates, although they are by no means completely free of danger. In addition to their namesake protection, suckerfish tend to stick to the bottom of the tank; turtles certainly can venture to the bottom of the tank, but most spend the bulk of their time within the upper layers of the aquarium.
Suckerfish primarily consume algae, which makes the fish popular with aquarists. These dietary habits also make them extremely unlikely to consume your turtles. Suckerfish represent very little -- if any -- threat to your turtles.
Tips and Tricks
While you should never overfeed your turtles, consider keeping edible aquatic plants in the tank. By offering easy treats for the turtles to consume, you may reduce their desire to chase fish between meals.
Improve the fishes chances of success by incorporating hiding spots. Live or artificial plants, caves, rockwork and driftwood all provide opportunities for fish to hide from hungry turtles.
Anecdotally, some keepers have success by keeping their turtles with fish from a very early age, instead of adding fish at a later date. This seems to help the turtles adjust to the presence of the fish, making them less likely to view them as prey.