I am looking for a turtle for my 4'x6' koi pond. It would have to stay small, under 10". Not attack my koi, which are about 6" to 10" right now. Not require direct sunlight, my pond doesn't get direct sunlight from september to February. Has to be able to be outside all year, I live in central florida. Lastly I want it to eat small fish, I have a pond full of guppys and convicts. Thanks