One thing I made sure of first was to check the temp of the water I used from the freshwater tank versus the tank they came from to insure they were close. I'm not saying this cured them but for now they appear normal.

I filled one of my holding cups with the tank water and just sat them in there for 7 to 8 minutes. I'm lucky they weren't as hard to catch as the other small ones...it would have been a headache!