phytoplankton

I found these turbine shape micro-organisms in my tank. They seems like hydra where they have a stem and branches, but hydra branches are thin but mine is big.

2 Eukaryotes fighting?, 1 in a turbine shape, 1 as a blob. They were found on my scraper while I was scraping algae. Edit: they weren't fighting, the keratella rotifer (blob) accidentally sucked onto the hydra (turbine shape).