Possible Ich On Pleco

I have not seen my new pleco much, but about a week ago I noticed some white spots on it.
Today I saw it in a good position for some photos.
Heres the best one:

Is this ich?
I have seen some of my endlers rub themselves on the the substrate, but it is very uncommon. I have seen them do this as far back as last year. No white spots on any other fish.

It looks like white spot.
Have you added anything new to the tank in the last 2-3 weeks?
If yes, then it probably came in with the new fish.

You can treat white spot by raising the water temperature to 30C (86F) and keep it there for 2 weeks or at least 1 week after all the spots have gone.

Before raising the temperature, do a massive water change and gravel clean the substrate. Clean the filter too. And increase aeration/ surface turbulence to maximise oxygen levels in the water.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

Ok, thanks for the fast reply!
The newest thing was the pleco, which I put straight in. I do not have a quarantine tank, although I do have some 5 gallon buckets I could have used.
I can raise the temperature, and now am setting a second 100 tank which I can store the pleco in, if I should.
I cannot clean the substrate, as my gravel vac broke in the process of cleaning the 100 gallon, which is unfortunate.
I might try a few small water changes over the day. When I first started, I tried some big water changes, which killed some of my shrimp, so I do not think I could a big one all at once.

Try to do a water change now and get the temperature up asap. The longer you wait before getting the temperature to 30C, the more chance of the fish dying.

The idea of a big water change and gravel clean before raising the temperature is to dilute the number of parasites in the gravel and water, which means there are fewer to infect the fish.

You can make a gravel cleaner out of a 1, 1.5 or 2 litre plastic drink bottle (like a plastic Coca Cola bottle) and a garden hose. Remove the cap and plastic ring from the top of the bottle and throw those 2 bits in the recycling. Cut the bottom off the bottle and throw the bottom bit in the recycling too. The remaining bottle is the gravel cleaner.
Stick a garden hose in the top of the bottle and run the hose out the door onto the lawn. Use the bottle to gravel clean the substrate.

I might try and risk a big water change.
About the DIY gravel vac-could you provide some photos, or a video? I’m not too good on following instructions in written words.
Thanks for the idea though. I have some parts laying around from my first gravel vac:

I also can isolate the pleco if needed. I have a 100 gallon with a few endlers in it. Not decor in it yet, but its there.

There's no point isolating the pleco because the disease is in the tank. You need to treat the main tank.

If you can't do a water change then don't bother, just get the temp up.

I don't have pictures of the home made gravel cleaner.

Heres an updated photo of the pleco:

Some of the white spots have disappeared. Not sure how much of it is visible in the photo, but its fins are getting ragged.
It is however, not hiding anymore.

Keep the temperature at 30C. The white spots fall off the fish after a few days and sit in the substrate where they multiply. A few days after that they release thousands of new parasites into the water. If the temperature drops during the next few days when this happens, the fish will get reinfected and be covered in spots.