Wrasse breathing heavily, mouth open. Mass protruding from gill

[Wrassenaround]

I have had this melanarus wrasse for 2+ years now and up until about 2 months ago there have been ZERO issues with it.
2 months ago I noticed its mouth staying open almost as if it had a jaw injury. It would still eat and swim around just fine causing no concern.
This week rolls around and its breathing has rapidly intensified and isn't eating. There is also this purplish mass coming out of the gill only on one side.

I took this video tonight. Unfortunately I think it's going to be a goner by sunrise. If not, what would be some ways to treat this. (I don't have a QT tank)
All other livestock in the tank are perfectly heathly. Water quality is in good shape. Twice daily feedings, no tank bullies. This would be the first "disease" a fish of mine has had (aside from ich occasionally)

#fishmedic

 

[Wrassenaround]

 

[Wrassenaround]

 

[littlebeard]

Similar issue happened to mine. Formalin dip for 30 minutes seemed to help the first time. Unfortunately it succumbed to this when it returned

 

[Jay Hemdal]

I have had this melanarus wrasse for 2+ years now and up until about 2 months ago there have been ZERO issues with it.
2 months ago I noticed its mouth staying open almost as if it had a jaw injury. It would still eat and swim around just fine causing no concern.
This week rolls around and its breathing has rapidly intensified and isn't eating. There is also this purplish mass coming out of the gill only on one side.

I took this video tonight. Unfortunately I think it's going to be a goner by sunrise. If not, what would be some ways to treat this. (I don't have a QT tank)
All other livestock in the tank are perfectly heathly. Water quality is in good shape. Twice daily feedings, no tank bullies. This would be the first "disease" a fish of mine has had (aside from ich occasionally)

#fishmedic

That's a tumor of some sort. Its growth is impairing the fish's breathing to the point where it is moribund. I would euthanize the wrasse, as there is no possible treatment. Luckily, it won't be contagious. For a point of reference, when I see a long term captive fish with a growth under its gill, it is almost always goiter, a thyroid tumor. Fish gets these in captivity, sometimes from a lack of iodine in the diet, but more often from some unknown "goitrogen", a compound in the water than blocks iodine uptake and produces hyperthyroid growth. It could also be a regular cancer tumor.

Here is a post on euthanasia:

Fish Euthanasia

Euthanasia Euthanasia is a word derived from two Greek words that roughly translates to “good death”. In other words, euthanasia is the painless killing of an organism. In general usage, there is also the underlying understanding that euthanasia is performed on terminal patients only. This...

www.reef2reef.com

Jay