Reptiles, amphibians and fish all grow to accommodate their habitats when they are captive, the only way to stunt the growth of an animal without causing any harm whatsoever is to place it in a habitat that would be too small if it were an adult. This only works with babies and I have yet to find adverse affects. (I've been doing it for about ten years). The pleco is about 4 years old, albino, female, still breeds, and is perfectly healthy. It is 3 inches long and the axis is 6. The pleco is way too wide for the axis to try to eat it however.
This isnt too much of a dwarfing (considering bristlenose plecos only get about 6 inches long). Once i dwarfed a common pleco (usually a foot long) down to 5 inches. Its about 9 years old now, it was one of my first projects. I gave him to a friend in Illinois.