You might wish to learn to hatch bbbs (baby brine shrimp) for the purpose of feeding baby guppies (adults love the treat of freshly hatched brine shrimp too). That does involve some expense and maybe even more importantly, some more time and space in one's home. But your guppies will initially grow faster.

If your Corys spawn, you now have a choice of trying to raise 50 to a couple 100 fry or destroying maybe all but 20 and then raising the 20 youngsters in a 10-gallon tank with guppy fry.

That sounds cold, but do you have a 55-gallon tank available for a spawn of the Corys? :) Even when my bristlenose (Ancistrus) would leave the 1-2" sphere of 3/8th" eggs, their numbers began to quickly tax the "carrying capacity" of the 29-gallon tank they were in.

Knowledge of the specific fish, proper diet and feeding, providing a place to spawn, some understanding of what must happen with water temperatures, water chemistry, and consistent partial water changes are all important if small catfish are going to spawn in an aquarium. But if the young are going to survive, then space becomes even more important. That is not too different from what happens if we try to save all of the fry from any pair of fish. (A pair of guppies produces young which all survive and breed and you become the proud owner of 10s of thousands of guppies in a year!) Suddenly several aquariums are enlisted to help house all of the fry!