Zebra Dianos are egglayers and as there is no perceptable difference in their coloring; are difficult to sex, but once mature, females are deeper in the belly than males.

If set up in a breeding environment, gender can be descerned by behavior, as the slimmer males will flash deeper body coloring at gravid females, but it's quick, so you have to pay careful attention to catch it.

They are also prolific egg scatterer's, so well nourished Zebras in a healthy tank environment tend to provide themselves and their tankmates with caviar treats far more than most fishkeepers realize.

Actually, the females just plain get bigger in size...not just the belly area. Once they are mature, its pretty easy to tell.

Sierra