I scoop some water into a disinfected margerine tub and then catch them with a net and let them swim around in there. Once i'm done with their tanks I scoop them up in either the clear little cup they came in or a ziplock bag with the zipper cut off and float them in the top. I've never had any trouble with catching my males, I had one that would swim right into it. Now Dacey is ornery, and fast, but it only takes me a few minutes usually to catch her.