I have a full grown adult male and a smaller female blue zebra. I have another one in the tank that is only 2 1/2", and am not certain if it is male or female. There are babies in the tank that are 1/2"long, and as I was feeding them this morning, I noticed more new babies! How often do they breed? I am sure it is the same female, as she had looked like she was holding. At this rate I'll be over run with blue zebras! :rofl::duh: