HLLE

[AMP Tank]

We recently purchased two tangs (a whitetail bristetooth tang, and a blue eyed bristletooth tang). They were both treated with copper prior to purchase. We put them in a quarantine tank for a couple weeks and also treated with prazipro. Both were doing well. The whitetail was skinny when we got it, but it gained weight quickly. We fed both of them a lot of nori as well as mysis/brine with selcon.
After about 2 weeks in the display tank, the whitetail developed spots around the eye which turned out to be the early stages of HLLE. It has been one week and it has got noticeably worse each day. And now, the blue eyed tang has just started to show early stages of HLLE as well (speckles around the eyes similar to the whitetail when it first showed signs of HLLE).
They both seem happy and stress free. They get along with each other and every one else in the tank. They are active and eat well (as I mentioned we already are giving them plenty of nori as well as mysis/brine shrimp with selcon). Also, the water parameters seem fine: 0 ammonia, 0 nitrites, 15 nitrates, 78 degrees steady, 1.025 salinity. We also checked stray voltage which is roughly 10 volts.
So at this point we are lost and and concerned. What should we do here? We are anxious about waiting longer (it has only been one week but the HLLE is getting worse).

Thanks for any advice

 

[angelsandtangs]

Correct the stray voltage with a ground probe would be a start should have 0 volts .. second do you carbon dose ?

 

[AMP Tank]

Correct the stray voltage with a ground probe would be a start should have 0 volts .. second do you carbon dose ?

Thanks for the reply. No, we do not have any carbon.
We will try a ground probe as well to get the voltage to 0. However, 10 volts seems normal. Each piece of electric equipment we have generates about 1-3 stray volts (pump, skimmer, heater, powerhead etc. We tested each individually as well as all of them together which generates the 10volt total). So that's why I wasn't concerned about voltage at first. But it definitely could only help to get the probe and knock it down to 0. So I'll give that a shot ASAP.

 

[polyppal]

carbon dosing isn't an issue for HLLE, but bituminous/lignite carbon in filtration (that exudes dust/particles into tank) may be an irritant to Tangs and contribute.

Ive learned that Tangs particularly are just very susceptible to HLLE, and many just develop it in time, though the fish still seems happy and strong. I have a Whitetail Bristletooth in very similar situation as you, did copper power QT/Prazi treatment, started to develop some facial skin loss HLLE but the rest of his body and fins are great. Eats great and super healthy otherwise. Im just going to put him in the display and hope the facial markings heal back as time goes on. Interestingly, he is a full grown/lg years-old fish, while a baby Tolmini went through the same treatment with zero issues or signs of HLLE.

@Paul B has a very interesting theory on HLLE (that I also subscribe to) don't know where its posted maybe he can help us out.

 

[Spare time]

What type/brand of carbon do you use?

When my tang had it, I removed my rox carbon (was slipping through and grinding in part of my reactor, which I think was the cause) I switched back to red sea carbon from rox (red sea carbon has VERY little dust) and soaked food in brightwekk omega 3 hufa fish food additive and vitachem (I already had been doing that I think?). The tang recovered. I think the carbon dust was my main issue. I should also say it was my first time using a reactor and the rox carbon did not work well with the one I used (hence the dust issue)