Don't know what's going on. my shrimp don't want to stay on the bottom of the tank. they seem to have problems walking and when they end up on their back they can't seem to right themselves. they swim up from the bottom, hit the stream from my power head and then curl their tails and drifting back down to the bottom. Anyone have any advise or help they could give? Water conditions all test OK, All the other fish in the tank are ok as well, it's just the shrimp.