I got my royal plecostomus 4 years ago, and it grew only up to 6 inches and stopped there. I think the problem is that it,s not eating enough from the tank. I trid to give it small pellits but she never tride to eat them, those anyone have some suggestion what I can give it, because I would love to see it grow to it,s full size and space is not a problem because it,s a 300g tank.