I forget what it is called, but white plastic "grid', I think it is called egg crate, that you use under fluorescent lighting in ceilings. Get some. It is very cheap at any hardware store. Drop your water level to a foot or whatever, and cut a piece of egg crate to a foot (or whatever) and the width of the tank. With one hand you move it across the tank until you have all the fish in one small area. Net at will. Lift the egg crate. I have used this many times and never had an issue. Makes the whole job very quick.