What’s a tubifex worm? You may not know， but your aquarium fish sure will—and they’ll gobble up the San Francisco Bay Brand Freeze-Dried Tubifex Worms Fish Food. Freeze-dried tubifex worms make for nutritious， high-protein food for small or medium freshwater fish， discus， or amphibians. Arriving in cube form， these freeze-dried worms easily stick to the inside of your glass aquarium wall—simply sit back and watch the feeding frenzy commence! Plus， these worms are easy for your fish to digest， leading to less waste and easier aquarium cleanup.