I'm worried my brothers turtle tank doesn't have enough bacteria since he didn't cycle it before putting in the turtles. He has 3 baby turtles and a goldfish to clean up uneaten food in a 10 gallon tank with a 10 gallon filter.(Yeah, I know he needs a much bigger filter) Can I transfer bacteria from my fish tank to his turtle tank? If so, how could I do that? I don't think I can put few of gravel in there because the turtle might eat them. Also can I feed the turtles tadpoles?