Pond Larvae ?

Pond Larvae ?

Observation - Pond Larvae ?. Description: I assume these are larvae, of something. Must be 1000's of them. about 3 mm long, on and under the surface of water, all wriggling like tiny worms. very dark in colour, and covering an area about 15 cms in diameter. Tadpoles appear to be eating so

I assume these are larvae, of something. Must be 1000's of them. about 3 mm long, on and under the surface of water, all wriggling like tiny worms.
very dark in colour, and covering an area about 15 cms in diameter. Tadpoles appear to be eating some. wondered if Damsel fly larvae ? They are all crowded together in a mass.