Well, that plec in your pic is quite skinny. I'm not sure those couple of white spots are ich or not, but it's starving!
Can you post pics of your plec? It may not be like your pic, it's hard to tell sometimes...
The 1 thing I will say is change lots of water as much & as often as you can, that can really help with almost any health problem.
Please tell us all about your tank. Tank size? Fish size? Water test numbers? (what tests?) Other fish? Feeding? Water change schedule? Just everything...& then we'll ask more stuff...but we want to help you & your fish.