I have 5 Golden Burmese Zebra Loaches. I have had them for about 6 months. They are doing quite well, but there is an extreme discrepancy in their size. Three of the loaches have grown to be quite big (by my tanks standards) about 2" while two of them are still REALLY small. Like an inch. And the discrepancy isn't just length but girth. The 3 big loaches are fat and thick, the smaller ones are lean and skinny. Is this a dominance thing? Sexual dimorphism? Did some dwarf loaches sneak in the bag? These guys live in a 55 gallon aquarium that is heavily planted with rocks, caves, and driftwood. While the loaches tussle a little with each other for dominance, they don't seem to pick on the small ones. In fact, the bigger loaches tend to pay more attention to each other and ignore the smaller one. I'll try to post pictures later.