This is a unicellular organism called Nassulopsis, and it is heavily infected with parasites that are slowly feeding on the host and reproducing. All the round structures on and inside the cell are the parasites. . I love Nassulopsis because of the purple pigments in its cell. They swim around in nearby rivers, feeding on filamentous algae and minding their own business until they get parasitized by a group of unicellular organisms called suctorians. . Suctorians have different life stages. A ti

This is a marine worm, Dinophilus, and it’s parasitized by unicellular organisms called Grellia. You can see the parasites as blue, banana-shaped structures in this polarized view. . Dinophilus are a few millimeters in length and inhabit all marine environments. They eat algae and mind their own business without bothering anyone. However, the large population I had in one of my fishless tanks were all infected by a species of unicellular organism. . When I checked an odd-looking Dinophilus under