HELP MY OSCARS DYING!!

Question
I dont know how it happened but my oscar is swimming a little sideways, and he has a white bog like thing over his eye and i think its bleeding on the inside of it and he doesnt swim much anymore, only when i feed him he comes up, it looks like its rotting away (kind of like somethings eating it) PLEASE HELP!! WHAT SHOULD I DO? I NEED HELP IMMEDIATLY

Answer
Good evening Simpson, thank you for your question.

Your problems are almost guaranteed to be related to poor water quality.

Acquire a test kit or ask your local fish store to test your water for you and give you specific readings. Ammonia and nitrite must be at 0 ppm always, these levels are toxic to fish if detectable. In a cycled, healthy system, ammonia and nitrites are 0 ppm - this is always the case!

I hope you did the logical thing and performed some water changes while you waited for an answer. This is what you should do every time something seems out of whack in your fish tank. A 50% water change will provide immediate relief.

You don't mention how long you've had your aquarium set up, or how long you've had your oscar, or how big your aquarium is but this is what I am guessing. Your aquarium is too small to house an oscar to adulthood (55 gallons for one adult oscar) and you are not changing enough water - at least 30% per week, that is 17 gallons of water a week.

Clean your filter once a week, by rinsing it with used tank water. An aquarium big enough for an oscar should have two filters on it, you can clean one one week and the other one the next. Vacuum your gravel right away, and keep in mind you are supposed to do this once every two weeks.

http://freshaquarium.about.com/od/aquariumstartup/Aquarium_Startup.htm

This site will help you if you are new to keeping fish and aquariums. Guide yourself around it even if you are not, the site is searchable.

http://www.wetwebmedia.com/FWSubWebIndex/oscars.htm

This page discusses oscar care in general. Read the linked files at the top as well, there is a section on disease.

Read, read, read, after you get your water quality in order by way of several large water changes (always with dechlorinator) and you will get a handle on this.

Applying medication may be necessary even after large water changes, but medication is deadly when there is ammonia presence in the water, so before you add anything (except perhaps 1 teaspoon of aquarium salt per 5 gallons, which I encourage you to add, this will help with ammonia and nitrite poisoning) you will need to raise water quality.

Thank you for writing,
Nicole