Hi guys I'm not sure if this is a deal but I am pretty sure it is a good one!
If you go into your local pets at home, look in the sumps at the bottom of the tanks and you will often see little baby fry swimming happily around in there. Fry are very small and will often get eaten by big fish so need to be kept inside a breeder net inside your tank or a little tank on there own. If you ask he person working in the fish department if you can take some baby fry of there hands, they will often scoop as many as they can out of the filter and give them to you for free! please share in the comments if this works at your local pets at home or local pet shop!