I have a tank with sulawesi snails only that I use to raise my ricefish fry. I have moved a few eggs and one fry over from the ricefish tank and all of a sudden the fry is missing and I see a gammarus sit on the floating plant where the eggs are. Are they a danger to raising fry??? I read online that some people like to have in fry tanks since they eat leftover food, other people say they can be a danger. I have no idea where they come from and wouldn't mind them gone.