Some of the fish are platys. If you can get a clearer close up of the other fish i could have a better stab at identifying them. Maybe a pearl danio? Someone will be able to identify them.
The fry will be platys. At least one platy is female, and the likelihood is she was already pregnant when you got it. They birth live young and so are more likely to survive in aquariums than fry from egg laying fish. Eggs tend to get eaten before they hatch. Going forward, female platys store sperm and can produce 3 or 4 batches of fry for upto a year after breeding. If you dont seperate M/F they will breed over and over. When fry get about 4 monrhs old they will also breed and also produce fry, those fry will also breed, etc etc. You can quickly get overrun with platys.
What do you want to do? Are you interested in keeping the fish and continue to let them breed?
A fish store might take the newcomers off you once they are of a size for them to sell.
If you dont want to keep producing fry you will need to seperate M/F fish into seperate tanks before they get to breeding age. Regardless the female you have could have another 3 batches of fry, if that happens you will again need to seperate them out.
If you dont want fish that breed then livebearing fish like platys, guppies, mollys and swordtails should be avoided, or at least stick to single sex. Preferably male so you dont run the risk of buying already pregnant fish. If you want to breed fish then livebearers are good fish to try this with. Put a few livebearers in a tank and you will get more livebearers. You will need more tanks to move fish to as your population grows, or find someone to take them off your hands. Unfortunately livebearers are easily bred and pretty common, so they wont sell for much. You might find a store willing to give a little store credit for them, or possibly someone who feeds live fish to carnivorous fish might want them.
If you dont want them, and you cant get rid of them, then euthanising them is probably the only other choice.
