How long has this tank been set-up? (i.e. is it an older/cycled tank?) I was a newbie to keeping fish when I first set up my tanks last fall. I picked up two 10g tanks and dumped them with like 6 Mollies each and within a month, all the fish were basically dead (new tank syndrome from not having the tank cycle).
Have you tested the water for high
ammonia levels? I believe high ammonia can cause the redness around the mouth/gills/etc. Also, any high nitrites in the tank would be bad. And if the
pH in the water where the Molly was living is extremely different from your water's pH, it could be pH shock. There are sooooo many things for what it can be. People who always say that Mollies are "hardy fish" -- well, not in my case and I was a stickler for water changing/vacuuming 20% every week after the tanks finally cycled and I was still losing them left and right.
If it is laying on the bottom of the tank, from my past experiences with Mollies (oh, I've had probably 20 adults and hundreds of fry), once they're on the bottom, it's pretty much downhill from there. In the end, when my last adults all died (still not sure from what), they almost became paralyzed and their lower bodies wouldn't move. They'd try to swim to the top to feed or whatever, but then they'd just fall right back down on the rocks. (Some people thought it was a reverse swim bladder, where their bladders couldn't fill up with adequate air to help keep them floating -- instead of typical swim bladder where the bladder is permanently swollen and the fish can not swim down.)
Oh, this might help some too:
http://www.fishlore.com/Forum/3-fres...e-chart.0.html
I wish I had better answers, but testing your water is the first place I'd start and then go from there. Good luck!
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