What is this on my tang?

[OrionN]

I recently got a Convict Tang. It has a target lesion on the side. I would guess that it is a parasite that dug into the tissue. The lesion only visible from discoloration on the skin. No evidence of trauma or open on the skin. Pictures below.
it does not affect the fish in term of health and eating. My fish is getting over been emaciated from underfed at the LFS.
@Jay Hemdal
Is there anything I can do about it?
I encountered similar problem one time in the past. The fish stays healthy for many years with it and eventually died of old age. (Exquisite Fairy Wrasse). I will post picture of the wrasse later

 

[vetteguy53081]

I recently got a Convict Tang. It has a target lesion on the side. I would guess that it is a parasite that dug into the tissue. The lesion only visible from discoloration on the skin. No evidence of trauma or open on the skin. Pictures below.
it does not affect the fish in term of health and eating. My fish is getting over been emaciated from underfed at the LFS.
@Jay Hemdal
Is there anything I can do about it?
I encountered similar problem one time in the past. The fish stays healthy for many years with it and eventually died of old age. (Exquisite Fairy Wrasse). I will post picture of the wrasse later

Looks like either a sting from anemone or euphyllia or puncture injury (can be object or urchin and even a rabbitfish)
It should heal on its own but do keep an eye on it to assure it does not develop into an infection

 

[OrionN]

The lesion have not change for weeks so I am not sure that it was just transient injury and will heal. When I first got him I. 1/26/2023 it was not there.

 

[Lost in the Sauce]

I hope you figure it out. The last convict I brought in was healthy and over the course of a few weeks while getting fattened up, it also developed 3-4 of these dark looking circular marks. It never showed any other signs or symptoms of injury or illness. It passed in the night after about a month. I attributed it to a cyanide capture.

 

[MnFish1]

You could try a treatment with a broad-spectrum antibiotic that would cover mycobacterium marinium - But - that often takes 'weeks' or longer. You could also try a 2 week course of neomycin - to see if it changes. It almost looks like an ulcer - if it's staying the same - as others have said - observe - if there is any redness, etc - I would treat. Even if it IS staying the same - you could also try a course of treatment to see if it improves. Beautiful tank and clams

 

[Jay Hemdal Verified Community Expert]

Sorry, I’ve seen this before, but I don’t know the cause. I’ve suspected digenean trematodes that require an intermediary host so won’t spread…but no proof.
I do agree that convicts have some longevity issues that can be difficult to overcome, but you seem to have fattened this one up nicely.
Jay

 

[OrionN]

Thanks @Jay Hemdal.
I think you are right in that this is likely the intermediate host of some type of parasites. If something was to eat this fish, it will become the final host.
Here is my other previous experience with similar lesion. It started similar. It seem to wax and wane, between almost healed and then ulcerated. It never did affect the health of my wrasse. Eventually the wrasse died of old age. I had this wrasse from juvenile and he lasted for about 7 years, which is long for fairy wrasse.
It did not infected other fish in the tank. I should have do necropcy on this wrasse but I did not. If my convict tang have similar course, I will do necropsy on him when he die.

 

[OrionN]

I don’t have anything i the tank that would fine this injury. There are only 4 fish in the 40 gal QT system. Two clowns and my baby Harlequin Tusk (the smallest of the 4 fishes)
I had fish that was stung by carpet anemones before. Definitely not this type of injury.
This lesion has not changed for several weeks so it is not the usual injury that is healing. Something is preventing the tissue from healing as expected if this is a normal wound

 

[Jay Hemdal Verified Community Expert]

Thanks @Jay Hemdal.
I think you are right in that this is likely the intermediate host of some type of parasites. If something was to eat this fish, it will become the final host.
Here is my other previous experience with similar lesion. It started similar. It seem to wax and wane, between almost healed and then ulcerated. It never did affect the health of my wrasse. Eventually the wrasse died of old age. I had this wrasse from juvenile and he lasted for about 7 years, which is long for fairy wrasse.
It did not infected other fish in the tank. I should have do necropcy on this wrasse but I did not. If my convict tang have similar course, I will do necropsy on him when he die.

I’ve never seen a chronic ulcer quite like that. I wonder, it does look similar to some neoplasms that I’ve seen on cichlids, and they can live with those for years. The neoplasms are not “sunken”, they actually protrude though.
Jay

 

[OrionN]

The black lesion completely resolved. He is a fat tang now.

 

[Jay Hemdal Verified Community Expert]

O

The black lesion completely resolved. He is a fat tang now.

fat fish, looks great!
Jay

 

[OrionN]

I am not sure why my Convict Tang has gray coloration on the silver area. He looks dirty, instead of clean silver and black coloration. Maybe he will grow out of the gray coloration. I hope so anyway.

 

[vetteguy53081]

I am not sure why my Convict Tang has gray coloration on the silver area. He looks dirty, instead of clean silver and black coloration. Maybe he will grow out of the gray coloration. I hope so anyway.

Ive seen this more than once and does not impact the health but I believe has to do with their natural coloration which range from white to greenish-white, white to grey like mine and even a yellow pigment

Mine:
This poor guy is the last to get food as he is too submissive