Sick Goldfish - rubbing, clamping

Hello guys,

it's been a few days that my fish is acting off. I see it flashing on its sides and on gills a lot. Generally she looks upset and irritated, clamps fins and points with her head down, shakes head, twitches to the side, sometimes she opens her mouth as if she was talking/swearing. She looks miserable.

Please somebody help!! I've been trying to find help for long time but so far no luck!! Guys at fish store said it's from stress but I doubt it. One of my other fish flashes occasionally, too, but this one is worse. She developed red spots on both her sides probably from rubbing and she seems to have red spots on her head and leading to her top fin.

Could this be symptoms of flukes or something else?
I am new to fish keeping and I'm not sure.
Could PraziPro be helpful? What about salt bath?

I made this video and 2 minutes after recording this, she flashed, so you won't see that part.

Current params: Ammonia 0, Nitrite 0, Nitrate 20-25ish

 

Does kind of sound like parasites to me. Don't know if internal/external, but ich and flukes usually so signs, like little what grains for ich and flukes can show like a tail attached to the body. How long have you had the fish and always had them together?

 

Does kind of sound like parasites to me. Don't know if internal/external, but ich and flukes usually so signs, like little what grains for ich and flukes can show like a tail attached to the body. How long have you had the fish and always had them together?

Hello BigManAquatics.
I've only had these 4 fish together. But this big fish was previously housed with other fish who all died. I am her second owner. I've had them since end of August.
Yes, I think they have something too. I don't think it's ich however cause that would show as tiny grains of salt spreading. I don't think I see any round white spots.

 

Not too good myself with internal parasites, but it might be worth looking up.

 

Not too good myself with internal parasites, but it might be worth looking up.

Would internal parasites make them twitch and flash like this?
I thought flukes are external. Right?