I catch crayfish,snails and tadpoles for my spotties.They feast on all of them,and the best part is there free.I take a net with a 6ft pole, and just drag up a bunch of weeds around the edge of a pond.Big clumps are full of all different things.Baby fish,and baby crayfish all go into a 10 gallon tank I set up.I put a cpl small cat fish (about 1 inch long)in the spotty tank and they clean up the bottom and the turtles don't even look at them for whatever reason.I wouldn't worry to much about parasites,seeing these things are all part of there natural diet in the wild.Great looking spotty by the way!