Sick blue tang - help needed

[Kamko]

So a blue tang that I've had for quite a while bumped into a rock some time ago. First, there was only a small scar but since then the injured area has expanded as shown below:

Can anyone tell me whether this is a simple skin infection or something more serious? I've already tried using some immune system boosters to no avail, so how should I treat it? Thanks!

 

[JHemdal]

That sure looks like HLLE to me. It is unusual, but not impossible to have HLLE lesions on one side of the fish only. Is there any lesion or discoloration on the other side of the fish? Many years ago I documented a case where HLLE was apparently brought on by a bacterial infection in a Koran angelfish.

Jay Hemdal

 

[Kamko]

No, there are no discolorations on the other side. What is HLLE?

 

[Brian5280]

Head and lateral line erosion

 

[Kamko]

All right, I'll do a water change and start adding garlic extract to food. I checked my water parameters fairly recently so I tink water quality is ok. If that doesn't help then what should I do?