I'm a bit confused on bn pleco size. I know they are suppose to grow 5-6 inches but it seems that many of the odd balls (super red, lemon, ...) are a lot smaller - closer to 3 inches. I purchased a group of 4 (they sent 6) lemon blue-eye about 2 years ago. Of the 6 4 were small and 2 large. Is there something like a dwarf gene or is there some other reason (in breeding? health issues?) that results in the fishes staying small. Oddly the male and female in a 29 grew to full size but the ones in the large tanks stayed small.