Aeolosoma - The strangest worm in the world?

Aeolosoma is a genus of annelid worms like earthworms. But unlike earthworms, these are much smaller and can be found in different freshwater habitats like ponds and streams in many parts of the world. But it's not just in nature you are able to find these as they also inhabit almost all freshwater aquariums, and probably also a huge part of unchlorinated pools. In aquariums they are introduced with food or plants and can sometimes be found in extremely large numbers.

Tardigrades - Microscopic space travellers

Tardigrades are possibly some of the cutest and most popular microorganisms in the world. These microscopic animals can be found in all kinds of habitats all over the planet from high mountains to deep oceans, and even on the poles. However, even though they are very common almost everywhere you will need a microscope to spot them as most species are around 500 microns in size and the biggest ones rarely exceed 1 mm. Tardigrades are more commonly known as water bears, because of their bear-like appearance when they waddle around in the microworld looking for food. Some also call them moss piglets because of their high abundance in moss and lichen samples.

The darkfield illumination makes the individual storage cells clearly visible inside the body cavity, 

as well as the digestive system in the middle of the animal.

Tardigrades have eight legs which all end in a various number of claws depending on the species. Inside the body we find a lot of anatomical resemblance to larger animals as tardigrades both have a fully functioning nervous-, muscle-, and digestive system as well as primitive eyes. But despite a somewhat complex body structure, the animal only consists of a few thousand cells. Some of these are called storage cells which can be seen in the image above. These cells slush around inside of the animal when it walks. In the front tardigrades have a feeding apparatus consisting of stylets used to pierce the food and a pharynx used for chewing. Most tardigrades are herbivores and eat things like algae and other plant material. However, some species are hunters and eat things like bacteria, single celled organisms, rotifers and even other tardigrades.