He may not be a common pleco then. He looks like he could be a bristlenose or even some sort of peckolita. Plecos are armored catfish so their scales are thicker. That may be why it looks like his scales were pineconing a little. Many plecos (not all but many) are incredibly hardy in regards to their water conditions and they are able to withstand temp and water parameter fluctuations better than fish like fancy-bred bettas. If he could survive in his previous conditions, he probably won't be affected by the temp fluctuation. :)
Sorry, maybe not... I found an old picture and his scales kind of look like they're sticking out...
But they looked strange from the side so I looked at him from the front (he was sucking on the glass) and they looked like they were sticking out, and they look pretty defined from the side. Sorry, I don't know much about plecos and I couldn't get a picture because he scurried off to hide.. It's scary because I know that a temp fluctuation is what caused Okami to develop dropsy..
Also, he got him from a specialty fish store in Lincoln..
Do you know where your brother got the pleco? If he got it at Petsmart or Petco, then it likely is a common pleco and has a potential max length of a foot or more. They really only sell commons, sailfin, albino bristlenoses, and rubberlips. If he got it at a local fish store that specializes in fish, then it could be almost any kind of pleco with a max length of anywhere from 4" to 24". Offhand, it looks like it could be a bristlenose or a common.
When I got home today, the tank lights were out but I turned on a dim room light to quickly check on everyone and I noticed that my brothers plecos dorsal fin looks raggedy and uneven and the top of his head looked lighter colored or white in the dim light, but he scurried off quickly when I tried shining a small keychain light at him :/ I hope I didn't make anyone sick from that temp fluctuation!
Also, my brother says he's a type of pleco that doesn't get bigger than 6 inches... Here's an old picture of him.
Just an update.. We don't have any more friends for my brothers loaches, yet, and he doesn't have sand substrate yet either, but I did figure out that the heater actually works, lol. I decided to slightly turn the knob up (there isn't numbers on it, just a + & - sign) and it jumped from 72 to 80 overnight! Poor fishies. At least now its sitting at a stable 77 degrees :)
:( That's too bad. You can always QT the plants without anything until Walmart gets the Clear Water back in. Otherwise, before you put the plants in, go over them and pick off any snails you find and look for egg sacs.