from a personal experience i don't think either or will be hurt (fish/frogspawn)... i currently have two clown fish and they host on a frogspawn and it seems like the frogspawn actually enjoys it... it has gotten really big and opens up to the size of a softball with only 2 heads....as a matter of fact when i feed them they rush and dump food on the frogspawn, my fish have also hosted on open and closed brains, hammer heads, and torch, that i have had in the past..... but overall it should be all good..