I really need advice! Pls.

[Mazzi]

Ok so I've had two gold fish for about six years now and the other one got sick and eventually died.. Died at the bottom of the tank on its back. The other fish kept nudging it to get it to move. I took the dead one out and the live fish wouldn't move out of the spot the other died in. Bought another fish and it seemed ok at first.. Until a couple days later I found the new one dead. Since then, the old one hasn't been the same. He won't leave the spot the original one died in, he won't eat, and he's changing colors! Reach in the tank to touch him and he still doesn't move from that spot. I feel like he's going to kill himself.. What do I do? I heard if you put castor oil in water with them they'll die peacefully. Should I put him out of his misery? They say fish have no feelings but clearly they do. Pls help

 

[FreshyFresh]

What size tank? What type of goldfish (comet or fancy)? and most importantly, what is your water change schedule? Need lots of water changes with goldfish. As a blind guess, it sounds like your fish are suffering from ammonia or nitrite poisoning.