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[jaws7777]

The other day I moved the danios into the 55 to be the ammonia source. I never look at these fish they never stay still long enough but this morning I noticed one of their tails seem to be nipped or something maybe fin rot ? My concern is I dont want this to turn into something more serious and affect the fish I plan on putting in there Should I treat it with melafix or something like that ? I dont want to put anything in that will damage what ever bb that iv accumulated. Should I just remove the fish ?
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[jaws7777]

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[divemaster99]

Ever heard of ammonia burn (if not id look it up). It happened to one of my danios while cycling my 75, it healed pretty quickly after cycling though so I wouldn't worry a ton.