will hydra kill any fry or fish around?

Question

help!!! i found a couple on my daphnia tank and one in the main fish tank!!!

Answer 1

It's possible for it to kill smaller fry, but not an adult fish - it can still sting them, though. You should be able to remove it by siphoning it with a piece of airline tubing (and this will remove less water). If stubbon, scrape it off then siphon it. I'd turn the filter/airstone off temporarily (just while you're scraping) so the water movement doesn't blow it elsewhere in the tank and make it harder to find again.

It WILL eat the Daphnia!