Worms ~ Some common freshwater types with links to Micscape resources

There are a number of groups of worms that occur in freshwater. Many aren't microscopic but are shown here to give an overview of these groups. Some common organisms that may be confused for a worm are also included.

Note: this table isn't comprehensive, there are several other freshwater groups like ribbonworms and horsehair worms.



Key features

Micscape links


flattened, 2 or more eye spots, move in gliding fashion
1 - 15+ mm

image of flatworm

Segmented worms

oligochaetes: 1.5 mm. to >2cm long, hair bundles, (includes earthworm and Tubifex)

leeches: characteristic 'leech-like' motion, suckers each end
>1 cm

image of oligochaete


move very frantically, often in 'S' curves,
0.2 - 10 mm

image of nematode

not to be mistaken for worms:

Hydra, has tentacles
extended: 2 cm

Introduction to hydra

larger ciliated protozoa like Spirostomum (has very fast contraction)


insect stages like mosquito larva, these have a more distinct head than the worms above, also antennae/legs

Go to arthropods overview



First Page



Collecting tips

Insect stages


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