I have a couple tropical tanks and one contains a few Rainbow Fish! I have had them a little over a year and do not know how old they are as they were given to me but I think my friend had them at least two years before she gave them to me.

One of them has had an area on his back that looks raw. Almost came on in a 24 hour period. Scales and skin missing. Has anyone seen this before and if so what is it and do I do anything? The fish swims, eats and acts normal. Here are a couple pics,



Here he is with his mate.





They are in a 40 gal tank, Penguin 350 and AquaClear 70 running for filtration. Heater and Bubble wall used as well.

All water chemistry is good.

Ammonia 0
Nitrates 10
Nitrites 0
pH 7.8
Temp 78
Running for about 3 years
Weekly water changes of 25-30%
Prime for water conditioner.

Beside the Rainbow fish, there is a Pakistani Loach, four Clown Loaches, one Neon Tetra (Hes quite old, about 5 yrs) and they all all been together for over a year.

Any thoughts? I have noticed a very slight improvement, but not that much. Help would be greatly appreciated.

To me it seems like it might be injured? Is there anything in the tank it could have hurt itself on? I had a tank running for over a year before one of my fish injured itself on a decoration. If you think this might be the case, you can treat it with melafix. I have never had a rainbow fish so I am only guessing based on other fish I have had.

I hope it gets better soon!

Thanks Sunnygirl. I only have the big log in the tank and all edges are pretty smooth. Not sure that it has any areas rough enough to do that. I will try the Melafix and see what happens. Thanks again.

That's a pretty big wound to appear overnight,with nothing really in the tank to injure itself on.No way another fish may have been attacking it? Personally with looking at the pics,I myself would isolate it and treat with an Antibacterial med.I don't know if the Melafix would be enough for that size of open wound.
If you decide to treat the whole tank,you'll have to be careful with what you use with the Loaches htat are in there.
BTW,how big are the Loaches?

One of my goldies had something like this awhile back! I used an antibacterial med like Devs suggested and it did get better. I love rainbow fish! I hope yours gets better soon.

Thanks Sharon and Erin!

Lets see, Sharon first. I have never noticed the fish to pick on one another, but then I do not see what goes on at night. I have a fully cycled 30 gal sitting empty. I will move the Rainbow into this tank and treat with some antibiotic meds. Hope it helps him. As for the Clown Loaches, all of them but one are about 3 in from nose to tail, and the oldest one is about 4 1/2 in long. The Pakistani Loach is about 3 1/2 in long, was not sure which ones you meant.

Erin, Thanks again, I will try what you guys have suggested. These are the Rainbow fish Rachel gave me when they moved, thery are so pretty.