A spot ???

[FixIt]

I noticed this spot on my Purple Firefish yesterday. It is brand new and want there the day before. I did just recently add a RBTA to my tank. Could this spot be a sting from that ot something else?

 

[Maritimer]

Could be a sting ... I would expect that to look different between a firefish and a clown, which it does.

Could also be a bacterial infection, so do keep an eye on it.

~Bruce