What is the best and safest way(s) to clean a Betta fry tank?

They are 1 week old today. I have a sponge filter in with them. They get fed 3 times a day, liquid, powder, & brine shrimp. I use a turkey baster when changing water in my individual male tanks, but I almost sucked up several fry when trying to use that. My eyesight not being great, and them being so tiny.