What I Did: I built my own mesh cover for a Evolv 4 gallon fresh water tank. The mesh covers the water overflow into the back filtration system, so the small baby fish don't get sucked into the system.
How I Did It: I cut up a lizard ladder from Petco, because standard netting is too flimsy and difficult to secure. Then I folded a square of the material over the intake and secured it with silver wire that won't rust.
Tips and Tricks The mesh cover is easy, cheap, and effective.