I think it had to do with how pet stores treat them. The females at my Petsmart only cost $2.99, but they aren't bought nearly as frequently as the colourful males which they charge a lot more for. $7.99 for any males except the dragonscales which are $14.99. The males having clean water and are for the most part, alert and disease free. The females? Letharigic and clammed fins.
From the business pov, it would be a waste to put effort into taking care of animals that don't really bring in as much of a profit. Awful, but true.