What is this and how do I treat it?

[kmbyrnes]

My Yellowhead butterfly developed these red lesions yesterday. He is staying away from the other fish in the tank. He is also lethargic and not eating.
No other visible signs of disease or injury.
He was moved 3 weeks ago to the new 350 g tank, but had been fine in the 125 since coming out of QT the end of July.
Water parameters are Ammonia 0, Nitrite 0, Nitrate 5, Salinity 1.025 Temp 77 - 78.

Any advice welcome.

 

[ThRoewer]

Looks a little bit like Lymphocystis, but a bacterial infection is more likely.

Do you have a picture of his mouth before this happened? It would help to assess the amount of damage.

In any case this could be a very serious issue. With a mouth injury like this he will likely not eat and that will be sooner rather than later his demise.
On thing you could do to help him preserving energy is to lower the salinity (he got to go into a QT anyway) to 1.016 kg/l. At the same time I would start with a broadband antibiotic.

I know that there is a method where you put fish that won't or can't eat into a sugar solution bath with an osmotic pressure equal to saltwater for an hour or so, but I have never tried it myself. The theory behind this is that all saltwater fish need to drink to osmoregulate. So it could be nourished with a liquid sugar solution. The risk is to promote a bacterial explosion, so the solution would also be dosed with an antibiotic.
Again, I never tried it and don't have detailed instruction on this method. But on the other hand you may not have much to loose as saving a fish with serious mouth damage is a long shot anyway.

 

[ThRoewer]

Found this image online:

Based on that the damage seems to be substantial.

 

[Dmorty217]

Antibiotics seems to be the best course of action in a hospital tank to try and get the mouth to heal. If not the fish will more than likely not eat again and slowly waste away. Do you know how the injury occurred?

 

[kmbyrnes]

Thanks for the advice.
No clue on how it happened. At least he is still eating mysis this morning.
Looks like I will be going fishing in the 350 today. Too much going on the last 2 days to rip things up with family and friends over.

 

[kmbyrnes]

Update: That fish is too fast for an old guy like me.
I was forced to leave him in the DT.
He continued eating and after 2 days was swimming with the pack.
Today he looks as healthy as ever.