Turtles aren't as easy, hardy, or inexpensive as many people think, so please research thoroughly in the form of books, webpages, and veterinarians before considering a purchase. There are far too many of these guys in shelters and rescues getting passed around from home to home as they become more challenging. The lifespan has been recorded at 100+ years, with ages well into the 40's and 50's common with proper care - this is a life long commitment, and an animal you may even need place in your will.
Most sliders currently in the pet trade are wild caught, which puts them under a great deal of stress, so seeing a veterinarian who specializes in reptiles is a must to check for common health problems in newly purchased turtles (internal parasites, nutritional deficiencies, topical bacterial or fungal infections, beak overgrowth, respiratory and eye infections). So, make sure a vet who is proficient in turtle care is in your area before buying your slider.
Next, make sure you have everything you need to accomodate growth. The minimum starting size for a 4" turtle (the legal minimum size) is 30-50g, but it may be more cost-effective to buy the final adult aquarium size, a minimum of 75-100g. It would be better to have a small pond, though sometimes extremely large storage bins can offer adequate gallonage. Either way, you will need a mix of land and water so that the turtle can sun and rest. It is best to make a smooth gravel slope leading to the "land," which can be made of many different materials but must offer enough space for the full sized turtle to sun properly. Alternatives are floating or anchored commercially-produced platforms, though these may be harder for the turtle to get up on.
Please note that you must subtract the space taken up by land area and gravel when calculating tank size! Tank depth needs to be at least double the length of the turtle from head to tail. Tank length needs to be at least 5x's the turtle's length. And width should be at least 3x's the turtle's length.
Powerful filtration is a must for turtles as they are prone to bacterial infections from poor water quality. With an extremely strong filter, you can get away with cleaning 25-50% of the water each week, and performing full changes every month or two. Tank care is definately high maintenance to keep a turtle in prime health. What's more, water temperature is the difference between willingness to eat and starvation, getting chilled or overheating. 75-86 degrees is suggested, with an room temperature of at least 75 degrees and a basking area temperature of 85-88 degrees. Lower temperatures promote respritory illness.
UVB lighting is essential to proper calcium metabolism, and exposure to natural sunlight via supervised outdoor sessions in a pen when the temperature is sufficient is also reccomended. If room temperature is too cold, you will also need a black light heating lamp to keep the temp up during the night. Make sure all lights are plugged into a ground-fault interrupter, are well away from the water, and secured to prevent falling into the water. Also be sure that your turtle can not reach the light directly, as this will cause severe burns. And never use a lightbulb whose wattage exceeds the fixture's, as having all of this electricity near water is a shock hazzard allready.
Feeding, despite all of the "nutritionally complete" foods out there, needs to be a mix of 50% plants, 25% live animals, and 25% commericial pellets. Freshy leafy greens, carrots, squash, fruit, and aquatic plants are all excellent food choices, and can be fed in large chunks to wear the beak down by chewing. Feeder fish, crickets, juvie hissing cockroaches, mealworms, and (store-bought food quality) earth worms make good choices for live foods. Frozen fish are not reccomended as they are deficient in thiamine. Mammalian organ meat can be fed as an occasional snack but should not make up any significant portion of the diet. And any high quality pellet suggested for turtles should be fine.
Many sites also suggest supplimentation of vitamins and minerals in the form of gutloaded insects, reptile multi-vitamins, mineral blocks, and cuttlebones. Calcium is the most common deficiency of the species.
I could go on and on, but I'm sure you get the idea... they're magnificient animals, but they are high maintenance like all reptiles, so please do your research. I can post some decent links if you'd like, and I do suggest you talk to some vets, get on some herp forums, and maybe even buy some books on husbandry.
the vast majority of the people buying a tiny turtle are completely unprepared for even a 6" semi-adult, much less the 12" maximum size.
