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

My favorite unicellular organism is having a snack in real time. It has a perfectly fitting name: Lacrymaria olor, which translates to “tears of a swan,” referring to its tear-shaped body and swan-like neck. . Lacrymaria olor’s “neck” can extend up to 30 times its body length. If I had that skill, taking the trash out would be dramatically easier. 😂 At the tip of the neck are tiny, needle-like structures packed with cell-melting toxins. Lacrymaria usually hides its body among debris and repeate