I am about to start treating my 12 gallon freshwater tank for internal parasites using Tetra Parasite Guard. Since the medication can be harmful to inverts I have removed my mexican orange dwarf crayfish. The only place i have to keep him is in a small container (about 1 gallon but shallow) without any type of filtration.

1. How long can he stay in such a container?
2. How do I know when I can safely move my crayfish back in?