Murray Hallam uncovers some worms in his Aquaponics Grow Bed. These are Compost Worms that will breed and multiply rapidly near the water inlet in your grow bed. There is enough fish waste entering this spot to keep the worms active and thriving for some time. There is no need to feed them anything else. Fresh oxygen will allow them to breathe underwater. Notice how clean the gravel looks. This system is 4 years old and has never clogged up with fish waste.