Convict Tang with Scale Issues

[PatD]

I have had my convict tang for about 3 months and all was going well....
Eats everything, gets along with other fish and doesn't bother corals.

About a week ago he started to develop these dark patches which look some kind of scale disease.
He's eating as usual but somehow I find he is also losing weight suddenly.
No other livestock showing any signs and water parameters are all good.

Any thoughts on what it could be?

 

[Jay Hemdal Verified Community Expert]

I have had my convict tang for about 3 months and all was going well....
Eats everything, gets along with other fish and doesn't bother corals.

About a week ago he started to develop these dark patches which look some kind of scale disease.
He's eating as usual but somehow I find he is also losing weight suddenly.
No other livestock showing any signs and water parameters are all good.

Any thoughts on what it could be?

Hmmmm, not sure what that is. I haven’t worked with convict tangs in many years.
Was it treated for flukes?
Jay

 

[vetteguy53081]

Looks like a past convict I had that startled very easily and constantly scraped itself on everything in fear of a past sohal tang. Not saying its the case but looks very similar.
What other tangs are in the tank if any ?

 

[PatD]

This fish was in QT for one month before I placed in the DT and although I never freshwater dipped - I never saw any sign of parasites or anything else wrong until a week ago - some 3 months after being in the DT
There are plenty of corals in the DT (6 foot tank) but only 2 other fish - a Royal Gramma and a prawn goby, so no chance he is being bullied.
I am considering trying a FW dip but it will probably be impossible to net him so I would need a trap.
The other thing that doesn't add up to being flukes or such is he doesn't flash, itch or seem outwardly bothered in any way.
I keep leaning toward some kind of bacterial or fungal infection...but I don't know.
Its definitely concerning as it seems to get a little worse each day now.

 

[Jay Hemdal Verified Community Expert]

This fish was in QT for one month before I placed in the DT and although I never freshwater dipped - I never saw any sign of parasites or anything else wrong until a week ago - some 3 months after being in the DT
There are plenty of corals in the DT (6 foot tank) but only 2 other fish - a Royal Gramma and a prawn goby, so no chance he is being bullied.
I am considering trying a FW dip but it will probably be impossible to net him so I would need a trap.
The other thing that doesn't add up to being flukes or such is he doesn't flash, itch or seem outwardly bothered in any way.
I keep leaning toward some kind of bacterial or fungal infection...but I don't know.
Its definitely concerning as it seems to get a little worse each day now.

I would consider trying a Prazipro treatment (if you can get it in Canada) Reef safe, and then you don't have to try and catch the fish.

It could be a bacterial infection, but those are virtually always secondary to some other issue like flukes, or an injury. External fungus is very rare in marine fishes.

jay

 

[PatD]

I would consider trying a Prazipro treatment (if you can get it in Canada) Reef safe, and then you don't have to try and catch the fish.

It could be a bacterial infection, but those are virtually always secondary to some other issue like flukes, or an injury. External fungus is very rare in marine fishes.

jay

Thanks Jay

Any Praziquantel containing products were pulled from shelves here and cannot be imported any longer.

Tried netting him tonight even though I knew it would be hopeless and basically only managed to stress the crap out of him. He's been hiding in rockwork for last couple of hours.

My only hope is a fish trap, I suppose.

 

[PatD]

Well - after so many various attempts to catch him - including the purchase of a trap which managed to lure in every other critter in my tank but the tang - I finally gave up on this effort. The only result of that was to stress him out so bad he quit eating and got terribly thin.
However...I was finally able to acquire from PraziPro and decided to dose the DT as a last ditch effort a few days go.
It has made an incredible difference. The convict, who's condition has deteriorated to a point where he had much scarring and fin damage on top of becoming emaciated to the look of death - has turned around 180 degrees.
There is already very little sign of scale or fin damage anymore and he has resumed eating - voraciously in fact!
My hope is that he can now rebound from his skeletal condition and has not suffered permanent damage from whatever it was that ailed him.
Also - I am now resigned to the fact that I have to dose Prazi again and if it is indeed flukes or the like (which would seem likely given the reaction to Prazi treatment) that they are eliminated.
Couple of notes worth mentioning here....
Never once did this fish (nor any other in the tank) display a single flashing, scratching, swimming to powerhead flow behavior so typical of fluke infestation. Also none of the other fish ever showed any of the scale or fin damage that this fish did. A real mystery

BTW - most of my corals reacted to the introduction of Prazi but quickly returned to normal within a couple of days.
All except one Goniopora - which has remained completely retracted since the dosing. I hope it too will survive - especially as I am going to be doing another dose tomorrow (7 days past the first).
In retrospect - the one thing I wished I would have done (and might still consider) is to freshwater dip one of my other fish....even though they never displayed any symptoms - I would have to presume that if this is flukes or some other external parasite....it would have infested other fish and I should see something from a FW
dip.
Any thoughts out there?

 

[Jay Hemdal Verified Community Expert]

Well - after so many various attempts to catch him - including the purchase of a trap which managed to lure in every other critter in my tank but the tang - I finally gave up on this effort. The only result of that was to stress him out so bad he quit eating and got terribly thin.
However...I was finally able to acquire from PraziPro and decided to dose the DT as a last ditch effort a few days go.
It has made an incredible difference. The convict, who's condition has deteriorated to a point where he had much scarring and fin damage on top of becoming emaciated to the look of death - has turned around 180 degrees.
There is already very little sign of scale or fin damage anymore and he has resumed eating - voraciously in fact!
My hope is that he can now rebound from his skeletal condition and has not suffered permanent damage from whatever it was that ailed him.
Also - I am now resigned to the fact that I have to dose Prazi again and if it is indeed flukes or the like (which would seem likely given the reaction to Prazi treatment) that they are eliminated.
Couple of notes worth mentioning here....
Never once did this fish (nor any other in the tank) display a single flashing, scratching, swimming to powerhead flow behavior so typical of fluke infestation. Also none of the other fish ever showed any of the scale or fin damage that this fish did. A real mystery

BTW - most of my corals reacted to the introduction of Prazi but quickly returned to normal within a couple of days.
All except one Goniopora - which has remained completely retracted since the dosing. I hope it too will survive - especially as I am going to be doing another dose tomorrow (7 days past the first).
In retrospect - the one thing I wished I would have done (and might still consider) is to freshwater dip one of my other fish....even though they never displayed any symptoms - I would have to presume that if this is flukes or some other external parasite....it would have infested other fish and I should see something from a FW
dip.
Any thoughts out there?

You should use a microscope to examine the dip water for flukes. Only one species, Neobenedenia is visible in dip water with the naked eye, the other species are all too small. Very often, the key diagnostic is that you see an improvement after a prazi treatment or FW dip - that usually means there were flukes involved.

Be sure to provide good aeration during prazi treatments. I typically give a nine day spacing for the second treatment, but that is just a guess. Some people use 7 or 8 days.

Jay