i have an oscar and one of its eyes is bigger than the other and i think it has popeye i cant post a picture b/c my camera is out of batteries but that is what i think it is anyway, the water parameters are perfect everything is 0 and my nitrates(i think that is the one but i dont have the paper in front of me)is 20ppm and the PH is about 7.5 and i dont know how to get rid of it.

You need to give us more info on tank size,filtration, how big the fish is and weekly water changes and how much.

my tank is a 29 gallon and i know that is too small but every petstore i went to said that would be plenty big(guess they lied)any way i have a 150 gph whisper filter and i change about 30% water weekly the fish is about 5 inches long i have had it for about 3 years and have never had a problem before it has always been healthy

Well i'm afraid you need to get him a bigger tank asap. Try doing more water changes through the week and doing 50% each time with a gravel vac. Keep your filter clean by regularly cleaning the sponge in old tank water and hopefully you can get the bacteria count down. Maracyn can also help with bacterial problems.

i tried maracyn and it just made the popeye worse the eye got bigger and looked more black and blue and i used it the whole amount it said and for the amount of days so now im trying salt and it is working better than the meracyn the swelling went down some. i would love to get a bigger tank and i would have gotten that size of tank in the first place but every petstore i went to never really answered my question. i asked them all how big of a tank an oscar would need and instead of saying 55 g or something like that they would say "a gallon of water for every inch of fish" that is what they all said now i know 12g of water for an oscar did sound small but i figured(sp?) they knew what they were talking about so i figured a 29 g tank would be plenty big and since it was doing so well for so long and staying about the same size for the longest time i thought it would be ok. i have been asking a few petstores if they could take it in and get it a new home but they already had 2 large oscars in the big tanks that they had so they couldnt take it in. i dont know what to do.

Sorry to hear that ilovefish, especially about the inept pet store clerks. Popeye is tough to deal with, but I hope everything works out. Sandy's right, keeping the water pristinely clean can only help.
There's no sharp or rough decor in the tank he might have bumped against, is there?

Good luck