Thanks for the identification, don't worry about the sexing it, i'm not trying to breed, anyway I will keep on calling him Mr.T xD
I am not trying to breed because here in Spain lots of "big" plecos (about 6 inches long) are abandoned in pet shops, in fact I rescued mine a year ago and he hasn't grown nothing since I rescued. I was told that he was kept in a 20-25 liter tank all his life :S
The pet shop owner gave me for free so in fact it can be consider as an adoption