Guppies are some of the horniest fish in the tank and when females are present, they are generally impregnated as often as their tiny little bodies can bear, and then some. If you have more males than females in a tank, the constant mating and child-bearing will wear the females out until they literally die of exhaustion. Rule of thumb to prevent your females from being fucked to death, therefore, is to keep it at a 2:1 female:male ratio.
It's easy to do since female guppies are readily identifiable: shorter and less dramatic tails but more tellingly a tiny dark cloacal spot low on the belly to mark their girly parts. The difficulty begins when you have to sort out of the endless streams of babies that guppies will gift to you, their bewildered (as in "wtf am I going to do with so many guppies?") owner. If you don't isolate the sexes, you may soon find yourself awash in big-eyed babies.
One of our strategies for the newborn has been to feed the tiniest ones to Babaloo, our betta. Since Ketzl is the main guppy-raiser, when the betta sees her approach the tank, he fans out his fins in joy and bobs up and down in the water, so excited is he to get something live to hunt and strike. And though I enjoy his enthusiasm and his display of wild instincts, I still can't help feeling a little queasy about sentencing the live guppies to death by betta jaws. Borne of rape, doomed to die, oh how sad.
Recently, Ketzl fixed the male:female ratio in her tank to control the population, so Babaloo is making do with more store-bought food. Meanwhile, I decided to take on some of the male babies and create a small bachelor environment for them. They seem happy enough leading sexless lives, to judge by all the frolicking. But as they've gotten older (they're now in fishy adolescence, I suppose -- not adult size but no longer tiny blobs whose eyes seem bigger than their bodies), and presumably hornier, they've pretty much made the choice a lot of prisoners make, reckoning that some sex is better than no sex, and accepting what's available rather than just dreaming about what is not. A phenomenon known as deprivation homosexuality or situational homosexuality, when applied to our species.
They are flapping and seductively swishing those fancy tails around. One of the boys, in particular, has been chasing after the largest fish, trying to corner him and wrap his tail around him, swimming up and down in the tank, and basically doing the whole crazy guppy mating dance.
I suppose if I added a girl or two, they might revert to being the mindless, inexhaustible serial rapists that they are in nature. But I really like the idea of owning gay fish. The only thing cooler than that would be if there were tiny little chastity belts for these horndogs of the freshwater world.