Plec In Fits

[universally_challenged]

hello everybody, new to the forum, purely because of a problem i have.
I have a freshwater tank, and on saurday, a perfectly happy golden loach keeled over and went belly up.
Today, i noticed one of my pleco's twitching. he usually keeps to the shaddows, but today has been out in the light, with his tail curved round twitching, i mean really fitting, like spasms. when he is done he swims off, but still with a bent tail it never gets straight.

has anyone had a issue like this? do you think its some kind of nervious system breakdown?

UC

 

[england]

whats the tank stats? filteration? heating?
tank ritual?do you change water weekily etc and how much?

 

[WILDER]

How many gallons is the tank.
How many fish and which type.
Water stats in ammonia, nitrite, nitrate, and ph.
Any signs of flicking and rubbing.
Do the fish look skinny or bloated.
What does it look like when the fish go to the toilet.
Is there anus red and inflamed or enlarged.
Lost any fish to bent spines.