Hello, new guy here.
Tried to search for the problem in the "sick fish" forum, but after reading about 20-30 of the more recent threads returned by various search attempts, and didn't see the same symptom, I decided to start a new thread. Sorry if it has been asked before, I know my search skill can be lousy...
Anyway, the short story is that our yellow tang has misty red spots covering its entire body. Its a very fine red mist and very spread-out. There is not a "concentration" anywhere. Almost looks like diatom is growing on his body. We had this problem once before, antibiotic took care of it but its coming back. He's still eating but I was wondering if anyone know what type of infection it is. Knowing the cause I can treat him better.
As far as other details goes, I do not have water parameters, but we do water change very religiously (20-25% every week). We have the fish in the tank for over a year now, is eating dry food (flakes) and pretty much anything you throw at it (except maybe donuts). Brine shrimp, blood worm, frozen algae, formula 1, etc... you name it. Has a maroon clown, white goby, and cleaner shrimp as tankmates. He is not flashing yet, acts normally (not overly shy or anything), and still quite active if he can't see us. We don't have a quarantine tank, but he was properly acclimated into the tank about a year ago. Tank is a 20 gallon "long" with live rocks and live sands inside. Prior to moving the tank to the office, it was my mini-reef with a bunch of leather corals and two angel fish (one flame, one juv. Emperor - surprisingly the flame never got caught and they both lived happily for 3 years in that dinky place until I moved them to my new 150 gallon).
A bit more on the background (for he experts): this small aquarium that we keep in the office have been around for over a year, all of the animals were introduced back then and have been very healthy. That is until we got some turbo snail for slim/diatom algae control... one of it committed suicide by getting itself stuck under/behind a live rock. Due to its large body mass (and the fact that we didn't notice it until it starts to smell), water condition went down the drain and it killed the cleaner shrimp in 2 days. There after we did a massive water change (25% every day for 3 days) and the water condition seems to stabilize. EXCEPT the yellow tang developed red mist on his body.
Thereafter the local fish store sold us these "mystery antibiotic" and it cleaned up all the red mist on the yellow tank. Alongside with it, that antibiotic also killed ALL the diatom and green and slim algae covering the live rocks. The live rocks are bare and white again, and if the cleaner shrimp was still alive I am sure it would've been a goner. I am kind'a worry that it also killed all the beneficial bacteria. That was about a month ago.
About 2 weeks later we noticed the red mist is coming back on the yellow tang. So we went and bought a new cleaner shrimp hoping it might work on the yellow tang, but that new shrimp has been a lazy bum (sigh). Also, the red misting seems to get worse, although it only affects the yellow tang. The clown fish is still obnoxious as usual, and I cannot spot any of it on the goby.
As far as tank condition goes, we don't have any test kit in the office so I can't provide a whole lot of detail on it. But I wanted to think that the water quality is stable, mainly because we are very religious about water change. Once a week I bring about 5 gallons of pre-mixed RO
water from home (Kent Max. Hi-S RO
unit + Instant Ocean), and we change out about 25+% of water every week. We run a canister filter and a skimmer all the time, with occasional activated carbon in the canister filter (maybe 2-3 days every other month). I am relying on the live rock in the tank (about 10-15lb) to do biological filtration.
On and finally the yellow tank has always been kind'a "pale" from the day we bought it. I thought it was the light making it look pale, but I am not very sure. Its really fat though, active and eating.