turtles, frogs and fish

Question
we recently started a turtle tank. did our research. 20 gal 1 red eared slider baby. my daughter introduced a type of goldfish to this environment. I thought it would be okay. only a $2.50 investment. she then put two of her leopard frogs into the same habitat. I watched for a full day and everything seemed okay. next afternoon, fish was a floater. it had a red spot that looked like it might be a wound. who killed it? turtle or frog? she'd still like to put a fish in. shall we try something larger than the frogs/turtle, so that he won't be bullied? in your experience what might work?

Answer
Hi Kimberly:  Turtles eat everything from fish, frogs, insects... I have a 8 month old red eared slider who can devour 15 feeder goldfish in about 1 minute.  I would not mix anything with the turtle... especially frogs and fish.  The goldfish may have been killed by the turtle or it may have died because of the difference between the pH of the tank it was accustomed to and the turtles tank... dave