Swallowtail Angelfish brown/red area

Travis Warren · Apr 12, 2020

Hi,
I added my swallowtail Angelfish to main display tank and 4 days later she has a brown/red area one side and on the lower area. Please see pictures. My salfin Tang and foxface chase her a little bit for first couple of days but really not much now. She is eating really good and I feed 4 times a day since I have Anthias and wrasse.

Big G · Apr 12, 2020

Those "reddish" areas on angels in particular need to watched closely as they can go sideways very quickly. Having NFG powder on hand is a good plan. It works wonders on bacterial infections, especially on angels and tangs. Furan2 is one of the other antibiotics that can treat those red sores. Increasing redness, necrosis, opening of sores needs treatment asap.

AZMSGT · Apr 12, 2020

Most likely Uronema. Your fish will likely parish from it with it that dark already. Sorry to be the barer of bad news.

Also a good chance now the rest of the tank is infected. Start treating the entire tank.

Uronema

Uronema marinum (updated Jan 24 2025) What You Need To Know: * Causes red sores most often seen on chromis damsels & anthias (see photos below). Angelfish, butterflies and other fish species are sometimes also affected. * Formalin can be used as a prophylaxis and to limit transmission of...

humble.fish

Travis Warren · Apr 12, 2020

Thanks for the replies. Researching it now. Man that sucks. Trying to get him to quarantine and not wreck all my corals.

EmdeReef · Apr 13, 2020

Treat ASAP. Last 2 months I quarantined 7 (Lost 4) swallowtails and all had a similar condition. Starts as redness, followed by a dermal necrosis / ulceration. The fish appears active and normal, eats well then stops eating but continues to be active.

Initially I thought it was uronema (which in your case may be), but in my case scrapes on 4 fish that succumbed to it had no signs.

The 3 fish that survived I treated with formalin baths, methylene blue & furan+kana. If you have NFG as @Big G said even better.