need better pictures.
it's not the gourami iridovirus and doesn't look like anchorworm either.
Is the fish still eating well?
What does its poop look like?
It is probably a bruise from a minor injury.
FYI, don't put chemicals in the tank unless you know what the problem is. All fish medications are poisonous and stress the fish to some degree. Try to find out what the problem is, then treat if necessary.
it's not the gourami iridovirus and doesn't look like anchorworm either.
Is the fish still eating well?
What does its poop look like?
It is probably a bruise from a minor injury.
FYI, don't put chemicals in the tank unless you know what the problem is. All fish medications are poisonous and stress the fish to some degree. Try to find out what the problem is, then treat if necessary.