Suspicious fin problem

[Bisqueshoppe]

Hey so a new problem. Chunks of fins are disappearing. Placos shark guppies mollys. In the tank are guppies mollys catfish algae eater tetras danios pleco shark gouromi. All community and non aggressive. It looks like perfect snips nothing jagged.

 

[Delapool]

Did you track down the cause of fins missing?

 

[Bisqueshoppe]

I have not. It's not getting worse but still not sure what caused it.

 

[V227]

There is always a level of aggression, even among the non agressive varieties. My school of non agressive Columbian tetras have a pecking order starting with the dominant male stretching down five other Columbians to the smallest subordinate male. Not unusual to see an occasional fin nip on the weaker ones tails. My guess is that things will balance out.

 

[Arthur75]

It can be fin melt. The fins will be smaller with straight edge. They melt. It is a bacteriosis.