Need Advice for Sick Rainbowfish

I have 2 that seem to always have injuries to their mouths, in may in fact be a mild form of cotton mouth. Don't raise your temp, keep it at 75. I would add some salt, about 1tsp per gallon and melafix as well. good luck. My lfs told me they won't be getting anymore because they all die within 2 days..seems to be a widespread problem.
 
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