I have a male albino red snakeskin delta guppy... The ammonia in the tank is 0 and his tail is NOT fuzzy like fin rot -- I think he got nipped by a female or possibly got his tail ripped by something in the tank (driftwood or plant or substrate)... It's a super tinny "cut", like 1mm x 2mm or so. It isn't frayed, just a little bit gone.
How long does it take the tail to repair usually?
<--- That's the fish in my avatar