The max size is 3 inches and they don't have to be that big to start coloring and spawning. If you have a spare tank choose the one that is biggest and/or has the brightest blue body or yellow dorsal and separate him. If he colors, he is male. You may have to keep doing that until you have a small enough number of males in your tank for one to color with the rest of the population.
Thank you, but to catch a fish in my tank it is almost imposible, since it is really big and with lots of hiding spots, could you help me out, the easiest way to get gim out, and see if his a male.





