Advice on HLLE

[Stones]

Hi folks, it's been a pretty sad week or two for my reef tank. I had noticed my yellow tang looking not so fantastic for a few weeks prior but I thought this was just stress seeing as he's at the very bottom of the pecking order due to his size. It's face was a bit whiter than normal and its lateral line was sort of off white in color. However, about 2 weeks ago I noticed some small, off white pits starting to form behind the eyes of my blueface angel.

I've been in this hobby for nearly a decade and I've never had a fish come down with HLLE before. The only place I had ever seen it before was at the Winnipeg Casino's tunnel aquarium and anyone else who has been there can vouch that it's not a pretty sight. I've had this particular angel for ~3 years and it has grown from ~2.5" to ~7" in this time frame. This is by and far the fattest fish in my tank as it's probably pushing 1.5" thick at the belly.

Here are some pics of the fish from today illustrating what I believe is HLLE.





Now for some background information. I haven't added any fish to this tank for over a year and the only recent additions have been some frags I brought in that were thoroughly bathed in interceptor for 12 hours and then dipped in an iodine based pest solution prior to entering the tank. In my mind, this rules out the possibility of the HLLE being caused by something that I recently introduced. The symptoms also only started 2 weeks ago when the frags were introduced ~2 months ago. All other fish besides the blueface angel and the yellow tang aren't showing any signs of HLLE which is strange since I have 4 other tangs in the tank and the powder blue is usually the canary in the coal mine when it comes to any disease, parasite or random alignment of the stars that cause these fish to randomly give up the ghost.

Currently I have zero nitrates and 0.14 ppm phosphates but the increased phosphates are likely due to the increased feedings I've implemented to try and help the fish recover. Approximately 1 year ago I had a partial crash caused by a nitrate spike that I never fully got under control until Christmas of this year. The tank has been nutrient free for ~3 months and while there were nutrients present, this fish showed no signs or symptoms of HLLE.

Prior to the angel developing HLLE I was feeding a mixture of Ocean Nutrition Formula 2 pellets, New Life Spectrum Marine formula pellets and PE mysis shrimp once per day. I was also giving the fish a half sheet of green nori or a New Era Marine grazer wafer once or twice a week when I was home from work.

After the onset of the HLLE, I've upped the feedings to twice per day and also added Ocean Nutrition Formula 1 to the mix. I've also been soaking the 3 different pellets and PE mysis in Selcon and a garlic extract prior to feeding. I've been giving a 1/4 sheet of green nori, red nori and purple nori per day also as I'm now back at home until road bans are lifted after the snow melts.

From what I've read on numerous forums and reefing articles, HLLE is a bit of an enigma. No one really knows the cause of it but it is usually associated with a poor diet, vitamin deficiency, poor water quality, or use of activated carbon. It seems the jury is still on the fence regarding whether or not stray voltage can be the culprit.

Seeing as I've had this fish for a very long time and it has been thriving since day 1 in the tank, I didn't believe it could be a poor diet or vitamin deficiency causing the HLLE. This fish didn't show any symptoms of HLLE when my nitrates were ~20 ppm last year and I personally know people that keep large angels in FOWLR systems in excess of 50 ppm nitrates with no issues. I've also run activated carbon in all of my tanks for the past 9 years and never had an issue before but to be safe, I dumped out my reactor of ROX carbon and am now running only HC GFO.

I also decided I should check for stray voltage. Right off the bat I was getting 48V on the multimeter which really doesn't mean anything seeing as all magnetically driven pumps will generate a small electric field when submerged in saltwater as well as small amount of voltage gets generated via friction of the salt water moving through the PVC pipes. I then switched the multimeter over to AC current and got a reading of 0.36 Amps. Although not a whole lot of current (I couldn't feel it with my hands in the tank), this was bad news so I knew I had a shorted out device somewhere. Turns out it was my mag 18 return pump which after swapping it out with my spare, the multimeter was reading 0.00 Amps in the water.

It's now been 2 weeks since I first noticed the HLLE starting and swapped out the return pump as well as increased the feedings/soaked in vitamins and garlic extract. The yellow tang has since regained much of its coloration and is looking significantly more vibrant every day. The HLLE in the blueface angel however seems to be slowly progressing and getting worse despite my efforts.

Obviously I'd like to stop the progression of the HLLE and hope that the fish can recover without much permanent scarring as the pits aren't too deep at the moment. I'm at a bit of a loss to explain why the HLLE hasn't reversed and I'm very concerned for the wellbeing of this fish. It is definitely the main showpiece fish in my tank and I love having a large angel in a reef tank as you don't see that too terribly often. The fish is still eating with gusto and bullying all of its tankmates which is par for the course. I haven't observed any white or stringy feces (to rule out other possible causes) but I've also not had the time to spend watching and waiting for the fish to have a bowel movement.

Any insight would be greatly appreciated. I'm planning on ordering some Brightwell Aquatics multivitamins, vitamin C and AngelElixor supplements shortly to soak the food in as well in hopes to turn this condition around. This just goes to show that no matter how long you've been in the hobby for and how much you think you know, there is always something out there that can really rain on your parade...