Help with a Doctorfish Tang

[UM Aquarium Club]

We have a Doctorfish tang that has been in our 150 gallon reef for ~10-12 months and in the last week has developed a slightly splotchy patch in the center on its head. It has infrequently experienced "twitching" behavior when

swimming. Pictures are attached. We also have 5 Banggai cardinalfish, 4-5 assorted blennies and gobies local to South Florida, and a clownfish. In terms of invertebrates we have a fairly wide selection of coral and a large bubbletip anemone. We recently lost some anthias to the anemone only a week or two after they were introduced. The doctorfish has been homed with everything besides the cardinals for at least 4-5 months without trouble. Is it anything to worry about or is our tang simply clumsy?

 

[S-t-r-e-t-c-h]

Looks like the start of lateral line erosion. Are you by chance using activated carbon in the system? There are studies showing that carbon can be a cause:

http://www.advancedaquarist.com/blog/activated-carbon-affirmed-as-causative-agent-for-hlle-disease

Link to the study:
http://www.tandfonline.com/doi/abs/10.1080/08997659.2011.608608

 

[UM Aquarium Club]

We run a UV sterilizer, a refugium with live rock and a little algae, a nyos quantum 120 skimmer, a filter bag, and 2 bags of chemi-pure blue which is essentially activated carbon. We've been running the chemi-pure for about a month and a half and hadn't noticed anything until this week, could it take this long to have an impact or is it unlikely to be this?

 

[S-t-r-e-t-c-h]

I'd pull the chemi-pure out of the system and give it a few weeks to see what happens. Honestly, the tang looks really good otherwise, so I'm not sure I'd take any more aggressive actions at the moment.

The study mentions "Once the carbon was discontinued, the processes reversed in a mean time of 49 d." if that helps. I'm not sure how well the onset of symptoms have been mapped out, so can't really comment on that part of your question. Sorry!

 

[flfireman1]

How much greens are you feeding him? Are you feeding Nori at all? I agree that it looks like lateral line/head erosion. What are you feeding?

 

[UM Aquarium Club]

We decided to pull the chemi-pure and I'm gonna do our usual 20 gallon water change today. We usually feed nori every other day along with frozen brine/mysis about 5-6 times a week and occasionally feed some flakes and pellets. We had stopped feeding as much nori recently to try to coax the tang and our other gobies and blennies to munch on some hair algae thats been taking over and it looked like it was eating more of it after feeding less. Looks like that could have caused it so we're moving back to nori every other day or more frequently and gonna just keep manually removing the algae. Will update how its going in the next week or two.