Identify large white spot on tang head

Sablah · Mar 27, 2021

There is a white spot on its head that has been slowly growing. I got this tang about 5 months ago from diver's den. The spot was on it when I got it (and in the picture from DD), and I didn't really notice it as a problem. It's been slowly getting bigger, but so has the fish, so I thought of it as a blemish. A couple months ago I noticed it start to protrude a bit from the skin, so I started thinking maybe it's not a blemish. I was running carbon, but I removed it about 2 months ago in case it was HLLE, but it is still getting bigger. It has no other issues that I know of, and it gets along with all other tankmates except for a goby it will harass. Any idea what it is?

Salinity: 34ppt
Temp: 77-78
no3: 20
po4: 0.03
Alk: 5.6
Ca: 450
Mg: 1340

DD picture:

In quarantine pciture:

It's really hard to get a picture or video now, somehow the tang knows when there is a camera and will usually stay hidden, even if I'm not standing there, and will always stay hidden under white lights only. Sorry for vertical video

Make sure to switch to 1080p quality

Jay Hemdal · Mar 27, 2021

Tough to see. At first I thought in might be an infected nares (nose) but is it too high up for that? The chronic nature of it leans towards HLLE, but it is really too far forward on the fish, and there is usually more symmetry, you would see something on the other side of the fish. If it were an older fish, the real long term development might indicate some sort of tumor, but I wouldn't expect that on a younger fish. At this point, I just don't see any treatment course.

Jay

Sablah · Mar 27, 2021

I'll try and get better pictures. Any other fish I can photograph just fine, but this tang somehow knows. (I wonder if phone cameras emit IR or other types of light that fish can see, but we can't).

Sablah · Mar 27, 2021

Jay Hemdal said:
Tough to see. At first I thought in might be an infected nares (nose) but is it too high up for that? The chronic nature of it leans towards HLLE, but it is really too far forward on the fish, and there is usually more symmetry, you would see something on the other side of the fish. If it were an older fish, the real long term development might indicate some sort of tumor, but I wouldn't expect that on a younger fish. At this point, I just don't see any treatment course.

Jay

You might be onto something. It is about the exact spot where the nare is on the other side I think. I keep forgetting fish have noses.

Jay Hemdal · Mar 27, 2021

Sablah said:
You might be onto something. It is about the exact spot where the nare is on the other side I think. I keep forgetting fish have noses.

I would just watch it for now - many minor issues like this resolve on their own, and the possible treatments can cause more stress.

Jay

Sablah · Mar 27, 2021

Jay Hemdal said:
I would just watch it for now - many minor issues like this resolve on their own, and the possible treatments can cause more stress.

Jay

How long before I should take action? It's been steadily getting bigger for 5 months.

Jay Hemdal · Mar 27, 2021

Sablah said:
How long before I should take action? It's been steadily getting bigger for 5 months.

Five months is super-chronic. The tumor idea would fit that time frame. I don't know of any infective disease that would grow that slowly - except Mycobacterium marinum (fish TB). I don't see any other symptoms that would indicate that disease though, and there is no treatment for that in any event. Sorry, I don't have any treatment ideas for you!

Jay