Blue-green bacteria - Oscillatoria - Planktothrix
The genus Oscillatoria has filaments without heterocysts and resting spores. There is no mucilage around the filament. Each cell is more broad than long. The cells have gas vesicles and make water bloom.
Planktothrix and Oscillatoria are extremely common in rich nutrient water.
Video. Oscillatoria and the filament green-algae Spirogyra where the chloroplasts are formed like spirals.