The other day I noticed there was a small hole in one of the gills of my buffalo head. Ive had him for a few months and his behaviour has not changed much. Ive taken a few pictures. He is in a 44g tank with some bala sharks and baby plecos.

The only thing that ive done recently was change over the substrate from sand to small gravel. Ive got a Marineland biowheel 200 for the tank with an extra insert with zeo carb.

Ive since quarantined him put in 3 tblspoons of salt and tetracycline.

As a side note about a month ago I lost 2 ID sharks with a similar type of thing. One had a white sore on the side of his body 2mm in diameter which turned into a ulcer and then he died. A couple weeks after that the other got an ulcer on his nose and eventually died.

Please help.

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