Invasion of the Giants (microscopic crustaceans, that is).

The community in the jar in the kitchen window continues to evolve. First, there was a bloom of haematococcus. Then, the Vorticellae thrived. Now, a type of microscopic crustacean has come to dominate. I think that this creature is from the family chydoridae, which is in the order cladocera (water fleas). It 'might' be Chydorus sphaericus. Note the heart dorsal to the anterior gut. Note also that there are two eyes. The more posterior is a compound eye. The more anterior eye 'might' be a nauplius eye, which is to say, a more simple type of eye that develops during the larval stage. I found that a good source of information was the "small crustaceans in fresh water" section of the Norwegian Biodiversity Information Centre!!!