i recently bought two oscars (3 days ago) one is fine and perky and happy the other just hides under the wood feature i have in the tank doesn't eat much and is starting to look a little ratty in the fin area and is quite a bit thinner than the other using this site i have found out that i have the correct size tank and temperature and cycled it before adding any fish i can't see any visible signs of parasite or disease but these are my first oscars and i'm worried i'm doing something wrong as soon as i can i'm going to buy a test kit but that won't be possible until early next week (today is friday the 26th of october). anything you can recommend for me in the interum??? i'm kind of attatched to these guys already so any information at all would really help or at least calm my alarm!!

Until we know what your water conditions, it really is very difficult to suggest anything. I would urge you to get them as soon as possible and give us an ammonia, nitrite and nitrate readings. In the meantime, I would do extra tank maintenance doing small water changes every three days

It is possible that your other Oscar is more timid then the other. As a result, the other Oscar tries to take advantage of the situation and bully the other Oscar. Thus, seeing the other Oscar timid, the other Oscar snatches its share of the food, making the other Oscar lose more food making it thin. I once had 2 Oscars and the one was timid and the other was slightly bigger and more aggresive. I was in the same situation as yours. Another possibility is that your water has problem i cant tell as i hav not seen anything. Oscarfishlover will be able to help u with this.

I suspect that the previous post is correct and the other fish is getting bullied. In any group of Oscars their will always be a pecking order as Oscars by their nature are aggressive fish. there will always be a top dog in the tank with a hierarchy following and inevitably there will be one at the bottom. If you have juts two Oscars in a tank then it follows that one is going to be top dog and the other will be the bullied one. The only way out of this that i can see is to separate them and nurse the other one back to health.