How to Breed Feeder Fish
Anyone who keeps large predatory fish knows that providing them with live food, rather than the typical pellets and frozen food that large commercial pet stores offer, is ideal in helping to keep their "finned friends" happy and healthy. However, the costs associated with buying live feeder fish can get ridiculous if you're buying them every week. A good way to supply your predatory fish with live feeder fish is to just breed your own. It's quite simple, and once you have a large stock of "feeders" it will be almost impossible to run out.
Set up your 20-gallon tank. Make sure that you have a lot of real and/or plastic plants in the gravel of the tank so that when your parent stock starts to have babies, the young won't be eaten by the parents. Also, make sure to treat the water with the water conditioner to remove any harmful minerals and chlorine.
Turn the tank's heater on and set it to stay at roughly 70 degrees. This warm temperature will keep your guppies breeding and allow for a constant supply of feeder fish to be collected.
Go to your local pet store. Ask for about 10 dozen "feeder guppies." They usually cost somewhere in the range of $1 to $2 per dozen. Take the guppies home and place them in the tank.
Now it becomes a waiting game. For the first three months the births will be spaced out and you will have a small number of babies to feed your large predatory fish. After the first three months you will notice more and more baby fish being born.
Baby guppies are born live, and they tend to swim on top of the water's surface. Take your net and just skim the surface of your tank, and there you have it: a net full of baby feeder fish. The good thing is that you will undoubtedly miss some of the babies when netting them out. This will allow you to have "fresh blood" in your breeding colony, because once the young fish mature they will immediately start breeding. Once every year you should remove about half of your breeding feeder fish and replace them with new ones from your local pet store so that the bloodlines stay strong and you continue to get large strong babies.