Another reason is because they breed easily for they do not lay eggs, but rather they are livebearers.
My family started our ''project guppy'' two years ago.
It didn't get to a good start. We wasted quite a few of them. But after a few months of trial and error we finally managed to rear them quite successfully.
We have two bowls of them. The above is a big earthenware bowl which is located in the patio. Another is a small (2 litre) clear glass bowl.
Guppy rearing can be a very relaxing hobby as we can while our time away watching the guppies swim happily. Every once in a while you get some pleasant surprises too when scores of little guppies are born.