I think my weather loach is sick

[Kazzasboys]

I've had my set up now approaching a year without problem. 120ltr cold water with a mix of gold fish, shabumpkin, black moor and 1 weather loach.
OK so he is crackers most of the time, likes his corner under the pump does his nightly circuit of the tank but last right he was floating vertically. Then he lay on the bottom flat and his whole body started jumping and he looked like he was choking. Also looked swollen and his bum hole was really open. He often throws his head back to swallow a maggot but it seemed different. Then he farted loads then swam off in his normal fashion. I had done a water change just the same as I always had and today I've come to find my tank really cloudy? Then I see him choking again then farting and threw out his bottom cloud which I've seen him do before. But at times he just doesn't seem right. He seems bloated and restless. But the spasming and choking is concerning me

 

[Aiken Drum]

Welcome to the community.

Anything else you can tell us?

Water parameters? pH, ammonia, nitrite, nitrate, temperature?

Filtration? How much and how often do you change water?

You mention a mix of goldfish. Can you be more specific on numbers and size?

What do you feed your fish and how often?

Have you done anything different recently, added anything to the tank recently, or using a new product etc? Any tank or filter maintenance?

You mention the water has gone cloudy. Could you give more details? Is it a milky cloudiness? Tealike? Green water? Detritus floating about?