Need Help With My Pleco

[liveo]

I have just got a new peppermint pleco and he was fine, then about 10 mins after he was put into my tank he has just sat at the bottom twiching he is alive but is this normal?
Could really do with any advice on this

 

[liveo]

just to update he is not moving at all now,he looks dead but i know they play dead so i really dont want to move him etc etc as i dont want to stress him if he is still alive

 

[DrewMuayThai]

What's the temperature, ammonia and pH level of the tank? How big is your tank?? Did he look okay when you picked him out from the store?