[header] How to tell the gender of an angelfish [title] Wait until the angelfish are mature. [step] In order for angelfish to become mature and be able to mate, they need to be properly cared for and given adequate space. If they are cared for and given the right amount of space, they may reach maturity as early as 5 to 7 months of age. 
At this time, they will be mature enough to breed and spawn. [substeps] Adequate space would be about 7-10 gallons of water per angelfish.