guppies and swordtails

[fishbguy]

I have a female, lyre-tail pineapple swordtail and a male feeder guppy in my 20 gallon. I have noticed altely, one of my male guppies, who is a little under half an inch long, is constantly chasing my swordtail, who is about 3.5-4 inches long. I know that there is no chance for a hybrid, right? but still, it is funny seeing this leetle fish chasing another fish 36 times his size...lol

p.s. yes...it is for reproduction porpuses...rofl

edit: the same swordtail, that i have had for 3 months, has yet to give birth. you can see her gravid spot clearly and she is very plump but has never had fry. and yes...there is a male in the tank

[mousey]

male guppies being what they are will try to mate with anything that has fins! including black skirt tetras.
Sometimes females decide to hang onto the fry for one reason or another. I have no idea why. It is also said that they can keep breeding on one mating. That is true. One of my females went barren for 5 months after her mate died then decided to have another batch. I know they store sperm but i did not realize they could store it for so long- 5 months.

[fishbguy]

i have black skirt tetras and i've never seen that...thank god...lol I have had the guppies for 2 months and this is the first time i've ever seen him try it.