Red Marks on Green Chromis
 

Purchased 5 green chromis about 2 months ago. Today, I noticed red marks on one of them. Hours later, he is staying near the top and breathing heavy.
Disease or aggression? Something else?


Parameters are all perfect. Tank is 50 gallons and also has standard clownfish, tube anemone, and torch frag.

Hopefully the photo helps. No signs on other fish. Any help would be great!

Hard to tell.
I'd say disease... Because for having them for 2 months that guy looks quite thin.

I’m going to also go with some sort of skin disease or infection.

Uronema. Google it.

I concur. Your tank will always have this parasite even if you do not have fish. Best option now is to keep your fish healthy, happy and low stressed. Healthy fish in a good environment are resistant. Not sure if you can effectively treat the fish.

Work on improving the biodiversity in your tank. Competition is the best defense.

I see this post is a bit old, but for anyone else seeing this I had a similar problem with a blue chromis a few days ago and the infection spread to my other fish. The host chromis and a clown died before I could do anything about it. Then I dropped some Jungle Fungus Clear into the tank and it seemed to stop the progression of the disease. Now the fish are getting better, minus some loss of tail fin length.

Update: the meds just slowed the disease. I now have 100% loss. Note to self: quarantine for a few weeks before dropping new fish in the tank.

I may be wrong, but isn't Jungle Fungus Clear for freshwater use only? (or at least, I've never seen it marketed to saltwater, or heard before of it being used - but, I've definitely been wrong before!)

I'm sad to hear you had 100% loss. I have accepted it was uronema, but I've been very lucky in that I have had no other infections since this. I have even added two new members to the tank (a black and white occ. clown and a twin spot goby) and all has been well since this original chromi (I still have the others as well which are perfectly fine).

I read on some other forum that people have used Fungus Clear in saltwater, and it was all I had at the time so I gave it a whirl. It didn't solve my problem, but nothing was injured: coral, crabs, snails, anemone, macro algae are all fine. How are the new fish doing? I've heard that uronema stays in the tank without a host fish.

Uronema is a “free living” parasite which does not require a fish host. So, going fallow will not eradicate it. Most fish seem protected from it via their natural immune system. There is a possibility that Metronidazole may work. At certain concentrations it is apparently reef safe.

Likely the only way to manage the pest now is to have healthy fish, low stress, and high biological diversity. Avoid Chromis. Unfortunately adding fungicides or antibiotics (metro) to your tank will not help with the diversity.

If you spot the horrible uronema disease in the first day you can possibly beat it with this method.

Uronema marinum
 

Looks like your green chromis had uronema marinum as there are red sores seen on the chromis. Well, its a bit hard to treat but there possible treatments such as Metronidazole, acriflavine, Chloroquine phosphate and copper. But then I suggest you to put your fish on different tank a week or two.