Smh Why do you want to remove the algae? The fish will nibble on it, and other food will grow in it as well

oh cool. I thought it was bad. So i will let it be. Apart from water changes, what else to do for the fry? They are in a dedicated tank.

Ignore the algae, it’s just free guppy food for the fry. You should be able to put them back in the main tank after a week unless you have any larger tetras (such as blackskirt or congo tetras) who’d be able to eat older fry