I agree with Blub...
I picked up (6) Dwarf Neon Rainbows quite some time ago (like 6-8 months back). All (6) were happy and healthy and very active up until about 8 weeks ago when it appeared 1 became infected with some sort of Gill Disease and passed on.
Now about 8 weeks later, I see a second (and possibly a 3rd) displaying some of the same symptoms. Breathing hard (large gulps of air) and hiding behind my
HOB filter and staying close to the surface.
I'm hoping I just got a bad batch because these are awesome fish. I love the look of all rainbows, but i'm now sketchy whether or not I should replace them