fin nippers

[lildragonflies]

I have one large marble angel 4 little baby angels and 3 serpae tetras in my tank. This morning I saw that one of the baby gold angels has a missing piece. The top of it's tall dorsal fin has been nipped off! So my question is is this normal for angels (or tetras) to be fin nippers and... do they grow back?

 

[lildragonflies]

I have one large marble angel 4 little baby angels and 3 serpae tetras in my tank. This morning I saw that one of the baby gold angels has a missing piece. The top of it's tall dorsal fin has been nipped off! So my question is is this normal for angels (or tetras) to be fin nippers and... do they grow back?

The tank is 38 gals. I just did a pwc yesterday.