Brown marks on my Yellow Tang

[oakley]

This morning when I went to feed my fish I noticed my 3 1/2" Yellow Tang looks to have brown areas along it's spine and tail fins, the water quality in this aquarium is ok ammonia is a bit high (5ppm) nitrates and nitrites are good. This tank is a newer set up, 37 gl folr only about 8 weeks old, but was seeded out of a mature tank that has had no problems in the past. The only other fish in the tank are 3 small damsels, 2 small red leg hermits and a turbo snail. What is causing the brown coloring????

[okiestranger]

I'm not an expert my friend but ammonia is very toxic to fish. Sounds like your tank may not have finished its cycle. If you have another tank I would say put all animals in there and do massive water changes to keep ammonia down and let your display tank cycle.

[Marinefish]

Probably lateral line disease. Also I think the tank is too small for a tang.

[leebca]

Maybe what you are thinking is 'brown' is really a slightly reddish look? Reddish would be 'normal.' It may look like the fish is 'blushing' in an area or areas or even as streaks. If you think this isn't right, please post a photo. Otherwise. . .

This is a sign of poisoning. This usually leads to death and on it's way there, an internal/systemic bacterial infection. Even if it isn't this, still do the following:

Make a huge (over 80%) water change NOW and then do this again every other day for a total of three times. I don't know why your water quality is not good, but you need to discover the cause and correct it. If this is a young tank or something has died in it, it may be best to find the corpse and remove itmimmediately, or if unknown, get the fish out of there and into a better aged aquarium that can handle the bioload.

Since this is such a large water change, you need to follow the water change guidelines found in the sticky post. If you follow that guideline, the fish will not be stressed, but you might be able to save its life.

Hope it turns out well for you and the fish! Good luck!

[Reefing Madness]

To many fish to fast. Tank not cycled. Ammonia = very bad. What are your Trite and Trate readings?