HELP PLECOS HAVE RED EYE AND SPOTS!!!

[PiercedHeart]

I have 7 zebra plecos and 1 of them from what I noticed has bloodshot eyes and red spots around its body D: I'm not sure what i should do but I'm changing them all over to a new tank that is pure water from pre R/O that I bought (cause i cant get it from tap cause its too hard) So yeah...anyone know what the red is from D: ? please help!!! I dont want 200$ fish to die >_<

[TwoTankAmin]

Provide a bit more info especially pictures, please.

How long have you have fish, tank/water info, diet etc.

[Mr. Johnson]

Have you seen your fish fighting?

[Barbie]

Pure RO water? This sounds more like a cycling issue, if I had to guess. I hope he figured that out...

Barbie

[TwoTankAmin]

Barb- great to see you post here again. I thought maybe aliens had got you.

If he moved over the tank contents and filters, that would have pretty much kept things cycled. I am also puzzled by only one fish being affected. If the issue was ammonia I would expect to see more than just one fish showing symptoms.

Also, I should have said that pure RO is rarely a good idea long term for any fish.

But on a second read I am now not clear on whether the red spots appeared before or after the changeover, but my impression is it was before?

PiercedHeart, can you clarify this, please?