“Fish with ulcers due to Tetrahymena need to be culled because there’s no way of treating them. Sometimes they look like a white spot infection, but they penetrate deep within the fish tissue, even Into the brain.”
Fish with ulcers due to other causes (e.g. lice, anchor worm, flukes, bacteria, trauma, etc.) can be treated by various means, targeting the primary cause, together with symptomatic therapy.
The picture on page five looks like we’ve two heads in one body! Maybe Alistair and I have spent too much time in Tasmania 😛