- Joined
- Sep 8, 2006
- Messages
- 2,390
If "rainbows" are the same as "patriot" crabs I've kept some in a freshwater tank before. About tennis ball size, colored red, white, and blue? I couldn't keep them in the tank. They constantly climbed out and I would find them behind furniture, or just hanging out on top of the tank filter. They seriously intimidated me! Like a large tarantula with pinchers. Very bold attitudes.