Help with yellow tang...

[pacificdiver]

I've had a yellow tang for about 2 years. He's been the picture of health for all but the last 3 months. He started showing some signs of mild dorsal fin erosion, with no other fin damage anywhere. I upped my water changes and checked water parameters, but everything seemed to be fine. All other inhabitants are happy with no signs of fin or any other issues. About 2 weeks ago, things started to get a lot worse, and here he is today. I've removed him to 20G QT and treated with Maracyn II 2 days ago.

Am I on the right track here, thinking this bacterial? I've been reading up on fin issues, and it seems tangs can get HLLE that shows with dorsal and anal fin erosion, through I don't see any signs of lateral line.

If there are any suggestions with regard to proper treatment for this little guy, or if something other than bacterial disease is the likely cause, I'd really appreciate the input.

Water parameters of DT:
NH3, NO2, PO4: undetectable
NO3: <10 ppm
Temp: 77-78
pH: 8.0
Alk: 10

Diet: daily green sheet algae, mixture of dried pellets, no flakes, occasional frozen mysis

Co-habitants: pair of ocellaris, several fire shrimp, several chromis

 

[FishAndPhysics]

How big is the display tank, and are you running carbon? If you are, how are you preventing fine particulate from making it's way into the display? Carbon fine particulate is a principle cause of a lot of issues in tangs.

Did you add anything wet to the tank recently?

Not at all clear it's bacterial, but if it is, a pretty standard "catch-all" antibiotic mix is kanaplex, metroplex, and furan-2.

Unfortunately, even if it is bacterial, the antibiotics would only stop erosion, which might make it hard to tell if they are working.

 

[HumbleFish]

Looks like HLLE to me: http://humble.fish/hlle/

 

[pacificdiver]

How big is the display tank, and are you running carbon? If you are, how are you preventing fine particulate from making it's way into the display? Carbon fine particulate is a principle cause of a lot of issues in tangs.

Did you add anything wet to the tank recently?

Not at all clear it's bacterial, but if it is, a pretty standard "catch-all" antibiotic mix is kanaplex, metroplex, and furan-2.

Unfortunately, even if it is bacterial, the antibiotics would only stop erosion, which might make it hard to tell if they are working.

Looks like HLLE to me: http://humble.fish/hlle/

Thanks to both of your for your replies. Looks like I was chasing the wrong target for a while, unfortunately, thinking that this had to be fin rot. I've never experienced HLLE before, and always imagined it would present with the typical line erosion and head cavities. Those are not present, at least to any extent that I can see, but the picture you posted is pretty compelling, HumbleFish. My water quality is excellent, from everything I can tell, and this would explain why everyone else is quite happy. A little disappointed in myself for not figuring this out sooner.

As for the cause, I'm going to check voltage today if I can get my hands on a voltometer locally. I purposely don't run carbon more than a 3 days per month, and it's very high quality stuff. I've never used copper so unless it was something related to capture, that can't be it either. I'm thinking I need to vary the diet more, but I thought I was ok on that. I'm adding Selcon and will change out to some new dried foods and more frozen foods, continuing with sheet algae every day.

Thanks again to both of your for your input.

 

[FishAndPhysics]

FYI, if you have a chiller, it will probably ground the tank (although you should verify this). Otherwise, a titanium ground rod is an excellent idea. Primarily for your safety, has the added advantage of solving most stray voltage problems.

Edit: still curious how big the tank is. Also, how are you running your carbon? In a bag in sump or in a reactor?

 

[pacificdiver]

FYI, if you have a chiller, it will probably ground the tank (although you should verify this). Otherwise, a titanium ground rod is an excellent idea. Primarily for your safety, has the added advantage of solving most stray voltage problems.

Edit: still curious how big the tank is. Also, how are you running your carbon? In a bag in sump or in a reactor?

No chiller, I run 3 Kessil LEDs above the display with enough height that the temp never climbs above the set point of the heater. I'm thinking a ground rod is a great idea, regardless so I'm going to get that in place asap.

The DT is a 90 tall, with a 50G sump system growing chaeto under an A360H set opposite the DT. A bubble Magus skimmer takes care of the organics. About 8oz of carbon is added for the first 3 days of the month in a bag set in one of the overflow baffles. Can running short burst carbon like this cause HLLE? I figured I'd be ok with such short use, but maybe not.

I'm hoping that a few weeks in a 20G QT with 10% daily water changes and heavily supplemented foods (selcon and garlic) will help, but I'm not too hopeful. He's feeding well, so at least I'll be able to get the supplements in there quickly. I was looking at topicals, but the only one that seems to be a sure thing is about $550 per tube. I don't think I could slip that one past the goalie.

Thanks again for the input.

 

[FishAndPhysics]

Carbon in sump or overflow is a bad idea, IMO. Carbon fines are nasty stuff. I just bought one of the Avast marine media reactors (the kits are super cheap, like $60) and ran it close loop from a little maxi-jet in the sump and then back into my filter sock. So there are 3 mechanical filters: the gravity effect in the reactor, the foam pad in the top of the reactor, and the sock.

 

[pacificdiver]

Carbon in sump or overflow is a bad idea, IMO. Carbon fines are nasty stuff. I just bought one of the Avast marine media reactors (the kits are super cheap, like $60) and ran it close loop from a little maxi-jet in the sump and then back into my filter sock. So there are 3 mechanical filters: the gravity effect in the reactor, the foam pad in the top of the reactor, and the sock.

Thanks for this info. I had no idea I could be doing harm by putting it in the baffles. I have a media reactor that's unused - I'll set it up as you suggested. Such a bummer - major ride on the Fail Train here. Hopefully I can get this guy back up and running. Temperment is good, but his dorsal and ventral fins are looking pretty scary.

Thanks again for the help.

 

[FishAndPhysics]

I meant to link the study earlier:

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

 

[pacificdiver]

I meant to link the study earlier:

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

Thanks for the link - much appreciated!