I have had an oscar for about 2 months now. When I first brought him/her home, he/she had a mark on it's side that looked like it was maybe a bite mark. Since then it seems to have grown in size and perhaps gotten deeper into the tissue. Whatever it is, i dont think it can be good. Any ideas on what it could be, or how it could be treated? I will try to get a picture up...

a picture would be useful for us to evaluate your concern.
water parameters are also vital in the process.
for the meantime, i suggest you do water change to
keep the water in good condition while waiting for the
inputs of others.

it is a 60 gallon tank and i do a 12-15 gallon water change every week. i have had my water tested, and my nitrite/nitrate levels were a little high. i have since gotten a new emperor 400 filter and increased water change intervals. the nitrate/nitrite levels have dropped off, but the condition seems to be worse

i understand... but you have just gotten a good filtering system
and the fish had been exposed to bad water condition for too long.
healing will not take overnight. as long as the fish is taking the
food eagerly, it will heal in no time. just keep the water under
check from hereon. pristine water is the first and foremost defense
in any fish illnesses.

the picture shows it is not that bad... no deep craters yet.

thanks. does it look like hole in the head? I read the article on hith, but what is going on w/ my oscar doesn't resemble any of the pics...

If this is not clearing and is in fact getting worse, there is obviously something causing this to happen. It could be down to poor water conditions but I doubt it. If you look very closely, is there any slimminess to the skin around the areas that are affected? It may be some kind of bacterial infection that is stopping this from healing, but in reality it is difficult to say just by looking at a photo.

Obviously the first thing you need to do is make sure your water is in very good condition. Your ammonia and nitrite needs to be zero and no higher, your nitrate shouldn't rise above 40 ppm and your pH should be between 6.0 and 8.0. The problem with treating with medication when you've got poor water conditions is that the medication won't be as effective.

whatever it is, it looks like it has spread to it's fin, the one that comes in contact w/ the affected area. i'm afraid that it might spread to the other fish. he is acting completely normal, eating normally (he is very picky, and i try to keep his diet varied). i just changed the water again and removed half of the larger rocks in the tank... hoping that this will improve circulation. thanks for the help again, i realize it is hard to diagnose something without seeing it first hand (i am an automobile technician and am asked to do so all the time:) )

I think it must be some kind of infection if it is spreading. And you say the skin is actually missing? Is there any way you can isolate the fish? Luckily, it's only a juvenile so even if you've got quite a small tank, that will be okay for a while. It's a shame you don't live close to me, I have a 20 gallon tank complete set up that would be just perfect for you

yeah there is somewhat of an indentation in the tissue. also the fin is also missing some tissue. i'm at a loss. is it possible to change the water too much? i think part of my problem is this damn blue ahli i bought. he is way too agressive and i need to find someone to adopt him, because he is always chasing the others around. it is a shame he cost so much, but he is stressing everyone else out, including me.

Thor84 wrote:


what kind of tankmates does your oscar have? are you sure that they aren't picking on him?

Thor84 wrote:


sorry!! missed it.............
Sciaenochromis fryeri ( ahli) can be quite aggressive and personally i don't think is a good idea to mix sa cichlids with malawi cichlids. they require different kind of water.

well, i'm pretty sure i have made a rookie mistake, and i'm sure i'll hear about it.. but he is in there with a sailfin pleco (3in), a blue ahli(3.5in), and a green terror(2.5in). i have come to learn that the tank is barely big enough for all of them individually, let alone all 4 in the same tank... but like many others i have plans to get a 125gallon this summer when business picks up. everyone else looks very healthy, especially the ahli who eats anything that goes into the tank( including the algae wafers). the oscar does get harassed by the others, the ahli chases him, and the terror tries to get tough going nose to nose w/ the oscar, but the oscar just opens its mouth and the terror head just goes in and out of his mouth..