Today I observed bigger worms in my microworm culture. They were white in color, about 3-4mm in length much much thicker than microworms. On doing some searching I discovered that its the larvae of some insects that are also good for the fish. I picked one up and let into the tank and immediately all my fishes were wanting for it. Good now I have some live food for the adults also. I need to find out if it is nutritious and the effects of feeding such worms for my fish.
From this site
"During the warmer months of the year I often find another small worm in the culture as well. This is because the odour of the culture will attract the common housefly, which lays its eggs through the small holes of the container lid. The eggs then hatch and the larvae develop and grow on the culture medium. This may seem a little unpleasant to some people, but these worms are ideal for larger rainbowfishes, which love them. Their development doesn't appear to have any detrimental effects on microworm production."