You said it yourself its a jellybean convict meaning short bodied meaning it is line bred/hybridized with other species of fish. And that female def. looks dyed pink to me, it just isn't as bright as fish that are freshly died.
Yes, it is most likely sterile and will act as if it is spawning but instead of the eggs turning brown they will most likely be white as if no sperm was deposited on them, if you had read about the fish before you bought them you would have known beforehand that they are sterile.