Well of course they are cute, everything is as a baby, but before you purchase the silver dollar sized turtle and before your toddler turns it into a teething ring, please consider the following:
Adult size = ~12in (30cm)
Tank size = pond or large aquarium ~180gal (680litre)
Diet = crickets, worms, snails, greens, turtle pellets
Additional costs = heating, lighting, filtration, filtration, filtration
That being said, another consideration; turtles are dirty and messy, kids are dirty and messy, turtles do not make good pets for young children and are known to carry diseases that can be contracted by humans, like salmonella.
Still interested? Read on, this is where the fun starts.
Choosing a specimen
Swelling, redness, lethargy, mucus, and fungus are all things to avoid when choosing your new buddy. Males will have elongated front claws, thicker tails and a slightly concave plastron (bottom of shell). Females will grow larger than males. If you do not plan on breeding it is best to keep the sexes separate, males can harass females when sexually mature.
As with most things in the Aquatic hobbies, bigger is better, and turtle tanks are no different. When young smaller sliders can be housed in smaller tanks, but they do not stay small for long; have you seen the "turtle tanks" at the pet stores, basically a 20gal long fish tank with one side modified to allow the hang on type filter to function with lower water levels. These are pretty nifty for small turtles, but you need to consider long-term housing for your new little buddy. Outdoor ponds are excellent if your climate will allow for it, otherwise indoor ponds or a large shallow aquarium will due. To encourage natural behavior a tank that is 6ft long and 2ft wide will work well, this will allow for plenty of swimming and diving. The tank does not need to be terribly deep, 1 to 2 ft of water will do. I do not recommend aquarium gravel substrate it is too easily ingested. Medium sized river rocks work great, or nothing at all, I prefer bare bottoms. You will need to provide some dry real estate for a basking. This can be built from bricks, cinder blocks, flat stones, acrylic, etc.; it's up to you. Water logged turtles are prone to shell rot, fungus, and respiratory problems. It is also important to keep the air temperature in the tank warm, if the air is too cold turtles will prefer to stay in the warm water and not get out to bask. Like jumping out of a hot shower into a cold bathroom, brrrrr.
Oh yes, do not forget the heater, these bad boys prefer warm water, unless you are going to encourage hibernation, which I do not recommend for the beginner. Standard aquarium heaters work well, but be aware, turtles become speeding bullets when excited, they have no problem smashing into and breaking glass heaters. They will even bite through the electrical cord of a heater if they get the urge. Give your heaters a break, place them somewhere that is inaccessible, or create an outer shield by placing your heater inside a piece of PVC. Keep your water temperature between 73F and 84F. I prefer 78F personally.
Above the landmass in your tank you will want to mount a heat lamp for basking. Your turtle will appreciate the warmth of your artificial incandescent sunshine. What's that you say? Incandescent bulbs do not provide any UVB for Vitamin D3 synthesis and metabolism of calcium! You got that right buddy. Full spectrum fluorescents will need to be used and replaced every 6months to 1year. Allergic to light? D3 can also be supplemented into your turtles diet. But what about black lights? Nope, sorry, the only thing black lights are good for is illuminating fuzzy glowy posters. All right, black lights do have other uses, but not for our purposes here. Is there such a thing as a basking lamp that produces UV-B? Yup, there sure is, UV-B heat lamps. These appear to be ordinary incandescent bulbs, but they will also provide UV-B.
Feeder gold fish are bad for everyone, including turtles, sliders are omnivorous. Fish are oily and fatty and will cause long-term damage to your turtle. The best diet is a varied diet; crickets, mealworms, salad greens, earthworms, wax worms, Tubifex worms, snails, and a quality prepared turtle pellet are the way to go. Crickets should be gut loaded before feeding. Most pet stores keep their crickets in a bin of with only egg crate, potatoes, and maybe some oranges, crickets with empty stomachs will do no good for your turtle. Bring the crickets home and store them in a separate container, there are many products that can be used for gut loading crickets, there are even fancy gel type foods that offer nutrition and water (eliminating the need for other sources of water) these are great because nothing smells worse than wet crickets. I like to feed my crickets flake fish food, and greens/fruit/whatever my tortoises are eating and I have extra. High quality vitamin and calcium supplements should be included as well, especially if your lighting does not provide UV-B. Calcium and vitamin supplements are extremely important for younger animals to prevent metabolic bone disease.
Turtles are messy eaters, and whatever goes in must come out. And boy does it come out. Clean water is crucial to not only the health of your turtle, but to your health as well. You, yeah you, quit trying to start that siphon with your mouth, that is disgusting and dangerous! Gravel vacuum siphons are easy to start by putting one end in your bucket and the vacuum end in the tank, fill the vacuum end with water, lift out of the water, water starts to flow, dunk it back in the water, and bingo. Or follow the instructions on the back of the package, submerge the entire thing fill it with water, place finger over hole on outflow side, stick in buck, no problem. Sometimes when I am lazy I use a power head to get my siphons started. Suck out as much turtle mess as you can find, do it frequently. In addition to your spot cleaning a weekly water change routine should be enforced. I like 50% weekly with de-chlorinated water. Tank load and filtration will affect how often you need to change water. Turtles have to live in this water that they so frequently foul, so clean it often. Imagine'¦ no wait, I will spare you any graphic comparisons if you promise to change the water frequently. Nobody wants to live in a toilet.
Under gravel filters, get rid of them, crush them into tiny pieces and use them for bio media in your wet dry. Hang on type filters are pretty much useless do to the lower water level in your tank. Internal power filters, these are cute for baby turtles and ok when used in addition to a larger filtration system. Canister filters, my filter of choice for turtles, powerful and efficient. Canister filters will need to be cleaned frequently, as in weekly or bi-weekly, with your water changes. Fine filter media need not apply. Coarse porous filter sponges/media will work best; the finer and water-polishing types will clog way too fast. Wet/Dry trickle filters are a fine choice as well. Large pump, drilled overflow, coarse filter media, smashed up UG filter for bio media (or bio balls/blocks/spheres stringy plastic things, whatever) and you are in business. Whichever type of filtration you decide to go with, be prepared to clean it and maintain it. If maintenance is no fun you will not do it and everyone will suffer.
Clean warm water, well-balanced vitamin enriched food, and a basking area. Do not over crowd your tank.
Eye infection: Swollen eyes, possible discharge.
Causes: Bacterial infection. Poor water quality, incorrect temperature.
Mouth infection: Sores, furry matter in the mouth, refusal to feed.
Respiratory infection: Lethargy, wheezing, excessive mucus.
Treatment: Veterinary attention required, most likely anti biotic injections.
Shell infections: Soft areas of shell, possible odor.
Causes: Usually a trauma related wound that becomes infected by bacteria.
Treatment: Regular cleaning with povidone iodine solution, topical antibiotics
Calcium deficiency: Soft distorted shell, trouble feeding
Causes: lack of calcium
Ear abscess: Swelling on the side of the head
Causes: poor water quality
Treatment: Veterinary attention, possible surgery
What else could go wrong?
Shedding of shell Scutes: No worries, perfectly normal
Prolapses: Yuck. If your turtle starts showing off his intestine via his anus do not
Aggression: turtles, especially male turtles can become aggressive towards each other, if you notice any aggression it will be best to separate the two.
This is merely an overview; there is a lot more to slider husbandry if you choose to explore it. Your setup can be as elaborate or as barren as you like. They key here is appropriate husbandry for your turtle, clean water, good diet, plenty of heat/light, and you and your turtle will spend many wonderful years together. Some have actually been known to live up to 30 years.
One other note worth mentioning is to always wash your hands after handling turtles, not just a quick rinse either, a good scrub for around 30sec with soap and water as hot as you can stand it.
De Vosjoli, Philippe. 1992. Red-Eared Sliders