Just my .02 but my asfs are escape artists and can be ridiculously hard to catch as they can fit into the tiniest of spaces lol. I had a trio that managed to get the lid off a 20 gallon tank with a 2x2 and hardware cloth lid. Twice. Would of never thought it possible. Putting a weight on top fixed the problem. Mine dont dart out when i open the lid but if you turn your back for ten seconds they will already all be darting for cover at lighting speed. Their jumping ability has had me laughing at myself while trying to catch the quick little bastards.:D