Some weeks ago, friends from the Portuguese Killifish Association explained me how to culture blackworms. They’re in a shallow tray since then at room temperature, the water gets replaced few times per week with aged water. I rock the tray every few days, this is said to cut some worms in pieces making them regenerate and multiply. The tray has some rocky material to help that and to provide hiding space. It is biological aquarium filter material. Food: aquarium wafers containing Spirulina and courgette cubes. Amazingly, they did double in quantity over these two-three weeks!