i need urgent help one of my friends oscars has a ring like (catarac)parasite it is right in the middle of his eye and we have only just noticed it. it is about 2-3mm in diamatre, currently under going treatment for white spot. could it be linked. and what other things appear on the eye.

could you possibly take a photograph? has this just appeared? If it has, I would suggest waiting for a few days and see if it gets any worse. However in the meantime if you think it's some kind of parasite, there's nothing wrong with treating the tank with an anti-parasite medication just in case. Make sure the carbon is out of the filtration before you do it. Also, did you check your water for ammonia, nitrite, nitrate and pH?

A pic would be a real help

When you get white spot and the spots burst an infection can into the weakness in the skin cause by the spots. This maybe what has happened here

If you are treating the white spot with some white spot treatment this treatment will also help with the infection. When you have got rid of the white spot and the eye is still the same, use any medication that treat ulcers or skin sores. Dont forget to put carbon in your filter for a day before changing treatments

If you are treating the white spot with raised temperature then get a treatment for ulcers or skin sores

It is a good idea to test for Ph, ammonia, nitrite and nitrate as fish heal better in good water