Need fish to get rid of guppy fry?

I have some small week old guppy fry in a ten gallon with a male guppy a female crowntail betta and two emerald cories. Everyone but the new fry has been together since springbreak and the betta is completely fine with the other three fish. What are some fish I can add that would eat the fry (there's like twenty of them I can't keep them all!) but would leave the three older from from apiril, which I am keeping alone? I have a empty five gallon too but I'd prefer to not use it because I still need to scrap off the algae in the tank