Erica Mede, CVT
Photos and edited by Susan Horton, DVM

The Red Eared Slider (also known as RES and Red Ears) is an extremely prolific and widespread chelonian accounting for 70-85% of the turtle population in the United States !  The slider family in general is the most prolific species of freshwater turtle in the world!  Red Ears make wonderful pets being one of the hardiest chelonians available in the pet trade and at one point in time was exported in numbers as high as 10 million annually.  Many owners remark that their Red Ear is not only “tame” but social and even seek human companionship especially if raised from a young age!  Red Ears are well known for their bright red markings along the side of their necks which makes them an attractive pet and the availability of albino, pastel, and leucistic morphs make them a huge seller and a very common pet.  With the latest production of two headed turtles from breeders, these turtles have settled nicely back in the ranks of popular reptiles!

Natural History

Throughout the Mississippi Valley (from Illinois to the Gulf of Mexico), these beautiful turtles are seen in the quiet rivers, streams, ponds, and creeks enjoying the sunshine from a log.  In nature, these chelonians enjoy quiet fresh water with soft muddy bottoms and abundant aquatic vegetation.  Logs jutting up from the water and rocks make wonderful basking sites.  The Red Eared Sliders in the colder climates hibernate in the winter although this is a practice not commonly recommended or practiced in the home.  Many new owners are concerned when their pet is found on the bottom of the aquarium unmoving or floating on the top of the surface.  This does not necessarily indicate that the RES has died!  This species is commonly in these positions while sleeping.  If the turtle is easily roused when in this state it is safe to assume it is sleeping.

In 1975, the United States government banned the sale of any chelonian with a carapace (top shell) less than four inches long in hopes of preventing the spread of Salmonella and the destruction of native species in the wild.  With the age of easily accessible information via the World Wide Web, private breeders have been successfully breeding and incubating Red Eared Sliders and now offer their domestically bred chelonians online.  As to the legalities regarding this practice, that is for the government to decide.  Domestically bred Red Ears are always recommended over their wild caught counterparts.


These chelonians are medium to large fresh water inhabitants with a distinct and very prominent red marking along the side of the head starting behind the eye will generally reach 9-11 inches long.  The carapace (top shell) is oval in shape and the rim near the back legs (posterior rim) is slightly serrated (ridged).  When Red Ears are hatchlings they exhibit bright green carapaces with bright yellow markings and plastrons (bottom shell).  As juveniles and adults, the carapace turns to an olive or brown color with yellow markings and black blotches.  Old males may have completely blackened carapaces but both genders will darken with age.  The plastron of juveniles and adults is yellow with a single dark blotch on each scute.  Aside from the characteristic red marking on the head, Red Eared Sliders have narrow yellow stripes running down their limbs.  RES also have yellow chin stripes as well.

Sexing and Reproduction

Males are generally smaller than the females at maturity.  Males also exhibit longer front claws which may curve slightly and longer, thicker tails.  The elongated nails of the male are used to stroke the females face to entice her to mate during the spring and fall and should not be cut.  The male will swim backwards facing the female and extending out the forearms to stroke her face.  If the gesture is accepted, the two will sink to the bottom of the aquarium to mate with the male on top.  Males that are much larger than the female must be watched so accidental drowning does not occur.  Red Ears will typically lay 2-25 eggs) between April and July and will hatch 65-75 days later if properly incubated.
Females that are becoming restless and exhibiting nesting behavior (clawing at the basking spot, frantically searching, going off food, etc) should be removed from the enclosure and placed in a warm and dark box such as large plastic storage box with air holes.  Sand or moistened top soil (free of manure and pesticides) should be provided in the “nest box” to facilitate nest building and a less stressful egg laying process.  The female should be left overnight in the nest box and removed in the early morning for feeding (if eating) and swimming.  This may need to be repeated several times before eggs are successfully laid.  A female that feels insecure or does not have an appropriate nesting site will lay her eggs in the water or the basking site unceremoniously.


​It is recommended that all new turtles be quarantined away from the rest of the household chelonians for at least 60-90 days.  In this time period the owner can access the animals’ behavior and health status.  Chicago Exotics strongly urges owners to bring these animals in during quarantine for a wellness exam and a fecal evaluation.  Quarantine requires food, dishes, accessories, and cleaning of the chelonian to be done separately (typically after) from the other chelonians.


The larger the enclosure for juveniles and adults the better!  This species loves to swim, bask, and explore their enclosures.  Many even enjoy items such as ping pong balls floating on the water surface as a toy!  Young turtles can be kept in 20 gallon long aquariums but will quickly need to be relocated to a 40 gallon breeder aquarium when they reach the juvenile and sub adult stage.  Most adults can be housed happily in a 100 gallon aquarium.  Some owners opt to create custom enclosures for their pets as well.  Generally speaking, there should be 6 inches of aquarium floor per every 1 inch of turtle.  If the turtle has a carapace length of 9 inches, it will require 54 inches of aquarium floor space.  Other enclosures to consider for multiple turtles include modified plastic tubs, outdoor ponds, and Koi tubs.  With a bit of creativity, enclosure potential is endless!
With Red Eared Sliders, it is recommended to have a bare bottom tank, one without substrate.  If substrate is desired for enrichment or aesthetic purposes, large gravel can be used.  An under gravel filter is strongly recommended as well as weekly agitation and siphoning of debris.  An under gravel filter is not enough filtration to maintain a clean environment and will need to be supplemented with other filtration devices.  Every 2-4 weeks the rocks should be removed from the tank and scrubbed well with a toothbrush designated for the job and bleach diluted 1:20 with water.
The water for these turtles is important!  These are fresh water turtles who enjoy swimming so the chlorine free water depth should be equal to the total length of the carapace multiplied twice.  If the turtle is 9 inches long then the water needs to be 18 inches deep.  Change a third of the water once a week to keep the water clean.

Typically, the water temperature should be maintained between 72 and 76 degrees Fahrenheit.  A thermometer in the water is highly recommended at the location furthest away from any heat source and one near the heat source.  Water temperature can be maintained using a submersible water heater or under tank heater on a thermostat.  If a submersible water heater is used, it is recommended to place a piece of PVC pipe with several holes drilled into the sides of it over the heater to prevent accidental burns and biting.  A general room of thumb is a 75 watt heater will work for a 40 gallon tank, a 55 watt heater for a 55 gallon tank, and a 200 watt heater for a 100 gallon aquarium.

Canister filters are recommended by Chicago Exotics for all chelonians as they offer mechanical and biofiltration.  Canister filters are generally less stressful to aquatics as there is no mechanical vibration on the tank from the filter body itself.  Fluval, Magnum, and Eheim make excellent filters and there are a few websites that illustrate how to create your own canister filter.  External filtration helps to remove uneaten food and large waste particles as well as agitate surfaces and increase water oxygenation.

The basking light should be over a flat stone such as slate or log.  Basking sites should be between 90 and 95 degrees Fahrenheit and easily accessible to the chelonian.  Metal clamp lamps work well for these sites.  The ambient temperature of the tank can be increased with under tank heaters and/or the basking lamp also.  During the night, under tank heaters or ceramic heat emitters can be used to increase the ambient temperature as it will offer no light.

As with most reptiles, Red Eared Sliders do well on a light cycle that simulates 12 hours of daylight and 12 hours of darkness.  A high quality UVB bulb such as a 5.0 ReptiSun bulb is recommended for adults and a 10.0 ReptiSun bulb is recommended for hatchlings and young turtles.  These bulbs help the body convert vitamin D3 into calcium and helps
prevent the disfiguring and deadly metabolic bone disease which is generally caused by a lack of available calcium in the reptiles’ body causing the body to absorb calcium from the bones.


Hatchlings and juveniles are highly carnivorous (prefer meat) and become omnivorous (eating both vegetation and meat) as adults.  The key to a healthy turtle is variety in their diet!  Aquatic plants such as algae and duck weed are relished by these chelonians but most owners offer romaine lettuce, cantaloupe, banana, kale, mango, and strawberries as treats.  Water hyacinth, water lettuce and water cress can easily be cultivated at home with some diligence and offer enrichment and nutrition.  Small fish (not goldfish), insects (crickets, earthworms, red worms), and snails are offered for the meat portion of their diet.

Supplementation with commercially produced turtle pellets is recommended as well.  Some people prefer to feed only commercially produced turtle pellets, in this case, Chicago Exotics recommends feeding multiple brands of turtle pellets.

In the wild, these chelonians embark on daily foraging expeditions throughout their habitat even stealing food from the mouth of other turtles!  In captivity, feeding varies with age and the energy output of the turtle.  Hatchlings are fed two times a day as much as they will eat in 10-15 minutes. Adults are fed once a day and as much as they can consume in 10-15 minutes.  It is recommended to come up with a standard food amount for adult chelonians to be fed daily to monitor appetite changes.  If the water is becoming fouled too quickly or the turtle is becoming obese then the food will need to be decreased.  All food should be sprinkled with a multi-vitamin once a week and calcium supplement daily for hatchlings and three times a week for adults.

Common Medical Concerns

(Also see Common Health Problems)

Very common in turtles who are housed together in small enclosures without adequate hiding spots.  Injuries caused by cage mate aggression are usually located on the legs, head, and tail.  Re-evaluation of the set-up is imperative and permanent separation may be the only solution.  All injuries should be evaluated by a veterinarian.

Shell Rot
Commonly seen as pitting of the shell, sores on the shell, or damaged/lost scute coverings.  This can be a life threatening as well as disfiguring illness and must be addressed by a veterinarian.  If this is occurring, a re-evaluation of water quality and filtration is recommended.

These swellings seen on one or both sides of the head are caused by poor water quality commonly.  These will not resolve on their own and must be treated by a veterinarian.

Metabolic bone disease is a major cause of deformity and death in hatchlings.  This is generally seen in turtles without access to UVB lighting, insufficient calcium supplementation, and those fed solely turtle pellets or dog/cat food.  This disease IS treatable by a veterinarian!  If the turtle is exhibiting a soft shell, limb deformities, or shell deformities, call for veterinary help as soon as possible.

Sources and Recommended Readings

Turtles of the World, Carl H. Ernst and Roger W. Barbour
Turtles of the United States and Canada, Carl H. Ernst, Jeffery E. Lovich, Roger W. Barbour
Keeping and Breeding Freshwater Turtles, Russ Gurley
The General Care and Maintenance of Red Eared Sliders and Other Popular Freshwater Turtles, P. de Vosjoli
Life History and Ecology of the Slider Turtle, J. W. Gibbons

​If you have any questions, please feel free to call us at (502) 241-4117.