HELP, goldfish laying at bottom of tank for most the day!

[FishKeeper72]

Hello friends,
One of my goldfish seems to be in distress! For two days no, he has just been at the bottom of the tank, dorsal fin down unless he moves for a little bit. No sign of any disease or parasite on him or other fish.
I checked the water chemistry levels and everything was normal. I lowered the water level a little so more oxygen could flow through from the filter (I also have 3 other bubblers). I cleaned out the filter to see if it would help. So far no change.
He still eats and siphons through the sand at feeding times. But after feeding time he just sits at the bottom. I am feeding him peas to see if that will help.
If you have any other ideas please let me know. None of the other fish are showing the same symptoms, just him. Tank size is a 75 gal

 

[Colin_T]

How long has the tank been set up?
How long have you had the fish for?

Have you added anything to the tank in the 2 weeks before this started?
Did you do anything to the tank 2 days ago just before this started?

What is the ammonia, nitrite, nitrate and pH of the water (in numbers)?
What sort of filter is on the tank?
How often and how do you clean the filter?

How often do you do water changes and how much do you change?
Do you gravel clean the substrate when you do a water change?
Do you dechlorinate the new water before adding it to the tank?

What do you feed the fish and how often do you feed them?

 

[10 Tanks]

Hello. Three things: Water change, water change and water change. I'd start by gradually removing and replacing a bit more water every water change and to do this a couple of times a week. These round bodied Goldfish can have digestion problems, because their internal organs aren't in a position that promotes good digestion of food and the removal of waste. I would also suggest adding Spirulina to the fish's diet. It's high in vitamins, amino acids and fiber. I feed it to all my fish.

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