Pleco being lighter patches

Edit: title is meant to be "pleco *having* lighter patches"

So I got this pleco with my tank about two months ago, and since then I've changed his tankmates and changed some decor (basically just added a piece of driftwood)..



He seemed to only get those light patches around his head after I put the driftwood in. I googled it briefly (I was nervous that he'd damaged himself on the fish gut I'd used to tie the driftwood to a rock) but it seemed to be a normal thing that plecos could change their coloration slightly in response to their environment. However, those areas seem to be permanently light now. Any theories as to why, or how I could help him change back? I preferred him when he was a uniform level of darkness, he looked less sick!

And by the way - any guesses on what type of pleco he is? I don't have much experience with them.

 

So the light patches seem to be slowly extending further down his body..



Think he's ok?

 

I've looked very closely, and it really doesn't seem fungal, because even in the light patches, i can still see the patterns on his skin, and there's no sign of filamentous growth or cotton wool type stuff.. He first started getting the light patches over a month ago, and he seems pretty happy, he moves a lot at night, and he leaves a lot of faecal matter so he must be eating..

Admittedly, he's in a 3ft tank which i know is too small long term (i got the tank with 3 plecos in it, gave two away!) but he's now 15cm long and I've got a friend with a pond who will inherit him when he gets bigger.. I do a 20% water change once a week..

 

Use acriflavine, you will lose him if you don't, it's a bacterial infection.

 

Did some tests on my water over the weekend before water change - ammonia 0mg/l, nitrates 20mg/l.

Here's a clearer picture of his head:


He really seems pretty happy, even though he's looked like this for a while! If anything, he's more active over the last two weeks than he has been in the last two months..

Any assistance on identifying what type of pleco he is? Thanks all for your input, i appreciate it..

 

I had the same issue with mine, did nothing, didn't even think it was an illness. 16 months later he is still around stuffing up and uprooting my plants.
It is a common pleco which will get very big and live quite long.
They however have been banned now as people chuck them into ponds and rivers when they outgrow their tanks and it becomes invasive.
So you shouldn't see them at LFS anymore.