HELP!FISH IS IN NEED OF URGENT HELP!!!!!!

Question
QUESTION: OK...to get to the point, my ryukin fancy goldfish has been staying on his side not moving at the bottom of the tank. i separated him from the other tank mate he has, a cory dora cat fish. i could see that my ryukin after being separated is trying to get up upright. also, my goldfish has his beautiful scales turn from calico to black. why might that be. to include the things needed in the question.the tank is a 20 gallon. i have a cory dora catfish and the ryukin only.(others sadly past on) my filtaration is, im not so sure about that and water change schedules are every month. the tank is about 1 year old.

ANSWER: The fish is dying from poor water quality and stress.

You should be doing 50% water changes once a week as a minimum.

Just start doing more water changes, and he may recover. It may be too late now however, but that is all you can do at this point. For water quality issues, prevention is much easier than cure.

Also, the corydora is a schooling fish. You should add at least 4 or 5 more corydora for him to live a full life.

-Nick

---------- FOLLOW-UP ----------

QUESTION: i cleaned my fishes water yesterday.and my other goldfish before passing away after 2 years has been living great with the way i treated it.i dont get how hes getting stress..

Answer
What do you not get about him being stressed?

Let me try and put things in perspective for you.

Goldfish are long lived. There is no reason your goldfish should not be living at LEAST 20 years. Goldfish have even lived around 40 years, and if you are taking really good care of him, he should pass away around 30 or so.

So, how old was your goldfish when he died? I'm guessing 2? Maybe 3 or 4 at the most? That's like a human living to be 12 and then saying he was happy and healthy.

Do you know what ammonia is? It is caused by fish waste, and can only truely be removed by water changes. After 4 or 5ppm of ammonia, NOTHING can survive, not even bacteria. In your tank, I'm guessing the ammonia would be around 2ppm. In a properly cared for and maintained tank, there should be NO ammonia whatsoever. In my tanks, I have not even a hundredth of a ppm of ammonia.

Why do you think the others died prematurely? Learn from your mistakes.

-Nick