there easy to keep just like a fish i lost count on how many i have i have them in an outdoor pond its 3ft deep by 15wide i feed them snails,worms,massivore pellets,guppies,clams, chopped up crayfish tails and newt & salamander bites i started of with 3 and in that pond theres 3 koi all so they eat the same thing i just feed them at night cause they dont come out in the day