Pleco Help!

[Smokey0923]

I bought this pleco from a lady that had him, 3 skirt tetras, a platty, a neon tetra a blood fin tetra and a black moor goldfish in a 10 gallon tank. Not long after i got them home i was told he's a spotted sail fin that he'd get huge. Here we are 6-8 months later he's only grown an inch making him 4"...... Did the small tank stunt his growth? Or is he a different type of pleco?

Another picture is someone I'm trying to help id hers as well. It's 3.5" and full grown. What kind is that one too?

 

[Weiro792]

Pictures may be helpful. But from my experience, it can slightly stunt their growth. But sailfin plecos do get pretty big, and I wouldn't keep him in that small of a tank. I had a sailfin in my 55 gallon and he got to big for my liking, even in that tank.
 
The other persons may be a female bristle nose pleco... they stay fairly small and honestly my bn looks a lot like what my sailfin looked like.