Feeding aquatic turtles is entirely different than feeding terrestrial turtles and tortoises. Land turtles require nothing more than a plate of proper food from which they can graze whenever they want. Feeding aquatic turtles is not quite so simple.
In general, aquatic turtles are more carnivorous than their terrestrial cousins. As they get older, Sliders, Painted turtles, and Red-Bellied turtles add more plant material to their diet. The large predatory turtles, such as Snappers and Matamatas, however, are exclusively carnivorous.
Aquatic turtles cannot use their tongue to manipulate food for swallowing, and depend on the rush of water to help push their prey down into their stomach. It is therefore difﬁcult for aquatic turtles to swallow their food unless they are underwater.
As you can imagine, eating is a messy affair for aquatic turtles. Since they have no teeth and cannot chew their food, turtles must tear their prey into bite-size pieces, using their powerful jaws and strong claws. This, of course, scatters a large amount of detritus and waste particles in the tank. These particles settle to the bottom and decay, quickly causing intolerable odor and cleanliness problems. In a large tank with several turtles, even the most powerful of ﬁlters will not be able to keep up with the mess.
The solution to this problem is to feed the turtles in a separate container that is large enough to hold just the turtle. Small aquariums make good feeding containers, but in a pinch such things as sweater boxes or large bowls can be pressed into service. The idea is to place the turtle into the feeding tank, which contains enough water for the turtle to submerge herself, and then introduce the food. The turtle is then able to rip and tear her food and make as much of a mess as she wants, dirtying up the feeding tank rather than her home tank. After the turtle is ﬁnished eating, she can be rinsed off with warm water to remove any food particles or detritus, and then returned to her home tank. The feeding tank is emptied, thoroughly cleaned, and is ready for the next mealtime.
Unfortunately, Snappers and Softshells, who tend to be the messiest eaters, should not be handled for feeding. If you keep these species, you will have to use powerful ﬁlters and resign yourself to replacing the water in the tank very often.
Fish as Food
Probably the best food for most aquatic turtles is live goldﬁsh and earthworms. With the viscera and bones, goldﬁsh provide a healthy, staple diet that is usually eagerly accepted. It is best to stun or kill the ﬁsh before feeding them to the turtles, since it may take awhile for your turtle to pursue and capture her food if it is alive—and some turtles, such as Musk and Mud turtles, may not be fast enough to catch live ﬁsh. (In the wild, Musk and Mud turtles mostly scavenge on prey that is already dead.) It is best to always feed your aquatic turtles in a separate feeding tank.
Larger turtles will eat correspondingly larger ﬁsh, and for convenience these ﬁsh can be kept frozen and then thawed just before feeding. It is very important that any frozen food be thoroughly thawed before feeding, because incompletely thawed food can cause severe intestinal problems.
Another good food is commercial trout pellets, which can sometimes be found in tropical ﬁsh stores. Many reptile stores also sell commercial turtle food sticks, which are usually made from ﬁsh products. These are also nutritionally complete and do not make as much mess as whole ﬁsh.
Commercial turtle foods that consist of dried “ant eggs” (actually the dried pupae) have virtually no nutritional value and should be strictly avoided, as should foods consisting of dried, vitamin-dusted ﬂies.
Most aquatic turtles will also eat snails (shell and all), and these are nutritious as well as being a good source of calcium. Occasional treats of raw, lean meat, such as heart or liver, can also be offered, but only rarely and never as a staple food.
Adult aquatic turtles will also eat vegetable matter. Small amounts of fresh, leafy greens, such as escarole, endive, dandelion leaf, and kale can be offered to any adult turtle at every other meal.
Like their terrestrial cousins, aquatic turtles can get by on a surprisingly small amount of food if necessary, easily going for two or three weeks without being fed while their keeper is away. Although they should be fed regularly two or three times a week, they can easily tolerate skipping a few meals now and then.
Since aquatic turtles have a high-protein diet that contains lots of meat, they can get by with much smaller amounts of food than their terrestrial cousins. Fifteen to twenty goldﬁsh or earthworms, spread out over the week, is sufﬁcient food for most adult Sliders. Young turtles, and smaller adults such as Musk turtles, will do well on two or three goldﬁsh or worms per meal. These can be supplemented once a week or so with a few trout pellets or small pieces of raw lean meat.
What About Supplements?
It is necessary to supplement your turtle’s diet with vitamins and minerals. Calcium, in combination with proper ultraviolet lighting, is especially important for young turtles, since it is used to produce healthy bones and shells.
Whole ﬁsh, bones included, is a good source of calcium, and should form the staple diet of any aquatic turtle. Additional calcium can be provided by placing a small piece of chalk or limestone in the turtle’s feeding tank, where it will dissolve and release small amounts of calcium into the water. Whenever the turtle is fed, she will swallow some of the dissolved calcium along with her food.
If you are feeding your turtles in a separate feeding tank, calcium supplements can be provided by lightly dusting the turtle’s food with a phosphorus free calcium powder.