this site is just so great lots of info
many thanks

we have 2 oscar which we have had 7 months no problem they seem to get on well last couple of days one is hiding in corner of tank there are white marks on one side of his body were they been biting the one is hiding at bottom corner very quiet please any advice would be great please

Any chance of a pic of the marks?? also are they raised like cotton wool?? it could be the start of a fungus or just small wounds, how big is your tank and how many fish are you keeping in there.(Fish size too) If you could give us as much info about your setup the better.

welcome to ofl.com

welcome to the site.

as marcus has said a little more info on your setup would be helpful in determining what the prob in your tank might be.

and a pic of the wound would be best.

A pic would be really helpful. Do the marks look like bits of skin are missing. Could your test your water for ammonia, nitrite and nitrate. How big is your tank

It sounds to me like one oscar is beating the other up. Try separating them either in different tanks or with a divider. When the weaker fish is better try putting them in together again (check some old threads for the best way to do this). If they fight again and the weaker one gets injured again then separation into a different tank or rehoming one is the only option. When it comes to aggression i have always got rid of the aggressive one.