Feeding Aquatic Turtles

By Gregory Rich, DVM; Laurie Hess, DVM; Rick Axelson, DVM

Aquatic turtles are referred to as turtles, terrapins, or chelonians. For this discussion, the common red-eared slider will be used as a representative animal in describing how to feed aquatic turtles, but this care sheet may also be used with African sideneck turtles, mud turtles, and musk turtles.

What do red-eared sliders eat?

Red-eared sliders are typically voracious eaters. They are classified as omnivores, meaning they eat both animal protein and vegetable matter. As juveniles, they are mainly carnivorous (eating predominantly animal protein) and become more omnivorous as they age.

All aquatic turtles eat and swallow with their heads underwater and will not eat out of the water. To facilitate optimal cleanliness of their tanks, aquatic turtles can be fed in a separate, small aquarium of warm water. That way, they soil this water rather than their main aquarium. When feeding turtles, it is important to offer a variety of food. Changing the types of food on a regular basis helps stimulate the turtle to eat and provides balanced nutrition.

An improper diet is the most common cause of health problems in captive aquatic turtles, as well as many other reptile species.

What are some acceptable animal-based foods I can offer my red-eared sliders?

The carnivorous portion of their diet should consist of high-grade commercial turtle or fish pellets, as well as a variety of invertebrates and vertebrates. Pelleted foods come in several sizes. Larger pellets tend to float well and are attractive to large turtles, whereas smaller pellets tend to sink quickly and are generally accepted by juveniles and small turtlesSome veterinary-recommended brands are Flukers®, Mazuri®, and ZooMed®. 

Aquatic turtles in the wild eat fish, and "feeder fish" may be purchased from pet stores or bait stores to feed pet turtles. Depending on the size of the turtle, fish such as goldfish, guppies, or minnows may be offered. Feeding live fish can provide your turtle with mental stimulation and exercise that comes with the challenge of chasing and catching its dinner. Fish also can be a good source of calcium for turtles, if they eat the entire fish, bones and all. However, feeder fish have recently been implicated as carriers of parasites and bacteria that can infect the pet turtles that eat them. Therefore, if you give feeder fish to turtles, it should be infrequently.

Smelt, mackerel, and other oily fish should be fed sparingly or avoided all together, as their high fat content may upset nutritional balance and lead to vitamin E deficiencies. A predominantly fish-based diet may also lead to a thiamine (vitamin B1) deficiency, so fish should be offered as only a small portion of aquatic turtles’ diets.

"Feeding wild-caught fish and amphibians is not recommended, as they may contain parasites and other infectious organisms that may affect the turtle."

Depending on the size of the turtle, amphibians such as tadpoles and frogs can be offered. Earthworms, snails, slugs, beetles, grasshoppers, moths, crickets, mealworms, wax worms, and other insects offer good nutritional content as well. Feeding wild-caught fish and amphibians is not recommended, as they may contain parasites and other infectious organisms that may affect the turtle.

Raw meat, fish, or chicken from the grocery store is not recommended as a food source for turtles, as it does not contain a good balance of calcium and phosphorus for a turtle. Regardless of the protein source, the carnivorous portion of a turtle’s diet should compose no more than two thirds of the diet of juveniles and about half of the diet of adults. Processed foods (such as hotdogs, lunch meat, and bread) should never be fed to any turtle species.

What types of plants can I feed my aquatic turtle?

The plant portion of the diet should be vegetables, preferably ones that float and can be left in the water for the turtle to nibble throughout the day. Desirable vegetables include dark, leafy greens such as romaine lettuce, collard greens, mustard greens, carrot tops, endive, Swiss chard, kale, parsley, green beans, dandelion greens, turnip greens, and clover. Avoid iceberg or head lettuce, as it is composed mostly of water and contains very little nutritional value. Scoop any leftover food out of the tank daily to promote proper hygiene.

The key to feeding turtles is to provide variety, as many turtles get bored and stop eating if they are fed the same foods day after day. Many aquatic turtles are drawn to the color red, so shredded red bell pepper (rich in vitamin A) is also good to offer. Safe, non-toxic aquatic plants, such as water hyacinth, water lilies, Elodea, or duckweed, can be placed in the tank.

Always check the safety of plants before offering them to your turtle to be sure they are non-toxic.

How often should I feed my aquatic turtle?

Feeding frequency depends on the age and size of your turtle. Smaller or juvenile turtles, in good health, will eat heartily every day. As they get older, adult turtles may be offered a good-sized portion of food every two or three days.

Do I need to give my turtle vitamins and minerals?

The key to proper nutrition for aquatic turtles is a diverse and varied diet containing a balance of vegetable and animal protein, depending on the pet’s age. Some veterinarians suggest adding a balanced, commercially available multivitamin once per week, with an additional source of calcium, such as a calcium block or cuttlebone, twice per week.

What are aquatic turtles’ water requirements?

Aquatic turtles, of course, swim in water and drink all day; therefore, the only water requirement for an aquatic turtle is to keep their tanks clean and at an appropriate temperature. Having a well-functioning filtration system that is cleaned regularly is critical to ensuring good water quality.

If you have any other questions about nutrition or care of your red-eared slider, seek the advice of a veterinarian familiar with turtles. Remember, turtles and other reptiles may be carriers of Salmonella bacteria. The bacteria may be on turtles’ skin or in the gastrointestinal tract, so it is important to always wash your hands thoroughly after feeding, cleaning, or handling turtles.

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