Don't think it is the enclosure size... I keep my 1.4's in 10 gallon tanks.... but I do hang my wheel from the top, and use a food hopper, so the entire floor of the tank is clear.

How old were they when you got them? Which mazuri are you feeding? Please explain exactly what your tank set up looks like. Where are they kept? What is the temperature? Can you take pics of their hiny's so we can confirm the sex?

Provide more info. We will figure it out!