I bet your babies say THANK YOU now, for that extra food source you put in there. Mosquito larvae is one of the best things a goldie can it, its a natural food, and found here around in ponds and lakes all over the place. A friend of mine uses water from a nearby canal for his ponds, and gets all that yummy stuff coming in with the water, and his goldies are crazy about it!!
The little worms are a product of too much waste, maybe decaying leaves in the pond where the plant came from. Since your baby tank doesnt have all those leaves, you will see those worms disappearing soon. My fish never bothered to eat them, since the worms are so small, but maybe its a perfect size for your babies to munch on...!