Res Turtle Minimum Tank Size

[FWFishLover]

Well My Sister Has Had A RES turtle for around 5 months now and we bought it as a baby and it seems to be a female and is around 4"-5.5" and is housed in a seemingly 15g tank
anyways, what tank will we need to get it for its adult years

 

[loraxchick]

female turtles have short front claws and a flat bottom shell(plastron). males have exaggerated front claws (very long compared to their feet) and a concave plastron. that will help you sex the turtle.
female RES can grow up to 12" in shell length. a 40 gal breeder tank will work for a while. turtles should have at least 2X their shell length deep of water, and about 3x accross to swim. should give you a good idea while out browsing for tanks (check craigslist and classified for good cheap turtle tanks. be sure to water test if you go this route, but obviously doesnt need to hold water to the top...just up to the basking area.
hope that helps.
cheers