Guppies are like aquatic bunnies. They will breed if they have water, light, air, and food. I like guppies. They are small, pretty, and easy to breed. I would suggest that you get a few males that you like, but make sure their colors are fairly similar if you want the babies to look similar. If you have two different colors and two different tail shapes, you could breed and then cull the undesirable babies. Eventually, you'll end up with the shape and color you want. Just keep in mind that you need to refresh the gene pool occasionally. Also, it's cheaper to buy a pregnant female and then you get a wide selection for free. You should really have an extra 10 gallon tank somewhere with just a light and a filter. No plants or gravel or anything else. I use one of these to put babies in until they are big enough to fend for themselves in the big tank. You need two if you are really serious about breeding, because the siblings will start breeding after a few months and you'll need to seperate the males and females. A female can store sperm and produce babies for a while afterward. So the only sure way to make sure you are getting babies from your male and female is to raise a virgin female and then put her in a seperate tank with the male of your choice. Otherwise, there is a good chance she'll have his babies, but no 100% guarantee. You'll notice breeding behavior when the male swims around the female and wiggles his tail while arching his body in a dance and shaking his tail. He has an extra fin on his belly which transfers the sperm and he'll dance and then try to touch her with it. She'll run for a while and then she'll accept him. If you have two males after the same female, one will interupt the others dance and begin his own. I usually get one of those v-shaped catchers to put the female in when she's near to giving birth. I have one that I bought from Drs. Foster & Smith, back when they were something like pet or animal warehouse or supply or something. Anyway, I think they still sale them and you can find them other places. You can get a cheap one that works at walmart. I like the ones that hang on the edge of the tank. They make ones that float, but they tend to go under the filter return and it pushes them down and sometimes the lid comes off. Mine has dividers that lets me make it a large breeding area, large delivery, double delivery, large holding area for babies. I also have another one that hooks to an air pump and shoot the babies into another holding area. Basically it's like a square container with a v-shaped piece of plastic in the bottom with a slit. The babies can't swim when they are little and sink down. They fall through the bottom of the v and the mother can't eat them. Guppies will eat the babies. I've also had the problem once of the slits at the bottom being too big and the babies go through them too. They are in the bottom for water exchange. You can then take the easy route or hard route. I will normally use the catcher regardless, but unless I'm breeding I don't use seperate tanks. If they have them on their own, I'll wait till the babies can swim okay and then let them loose in the big tank. I put lots of plants, especially heavy in one corner and some mat like grass. Lots of hiding places. I keep an old beta food container which I take my regular fish flakes and grind them between my fingers to make a fine powder. I keep it in here to feed the babies. Good luck.