~ Pond Life Identification Kit ~

A simple guide to small and microscopic pond life
with links to Micscape resources

One of the most rewarding subjects for study with a microscope are freshwater organisms. Simple collecting methods include squeezing water plants into a jar and for free swimming species, a fine-meshed plankton net is recommended. For simple tips see how to collect microscopic pond life

The table and linked pages are a guide to some common groups of smaller freshwater organisms (microscopic to a few millimetres in size). If not familiar with an organism, see what drawing and features it most closely resembles in the table and then follow the links. 

The beginner may also like to explore the virtual pond dip; click on the creatures in the jar to learn about some of the commoner freshwater organisms.



Key features 

Micscape links


single celled, dots or strands, just visible with strongest magnification, cyanobacteria are larger 

Introduction to bacteria


single celled, with tiny hairs or pseudopodia 


Go to protozoa overview: e.g. ciliates, amoeba, heliozoa, euglenoids


single celled, mostly green, sometimes yellow-brown 


Go to algae overview: eg. flagellates, diatoms, desmids, filamentous algae


wheel-like, hairy appendages, transparent, free swimming or attached 0.2 - 1 mm

'Smallest page on the web' - rotifers


two tails, hairy, round mouth opening
0.1 - 0.5 mm

No Micscape resources. (Articles welcomed!) 


long thin body, many non related forms 


Go to worms overview: e.g. flatworms, annelids, nematodes


plant-like or jelly-like colony, crown of tentacles
individuals: 0.25 - 5 mm

Pond fairies - Plumatella repens


green brown or colourless, body and tentacles contract and stretch 
extended: 20 mm

Introduction to hydra
Hydra in 3D
Hydra oligactis
Video clips of a hydra

Water bears

8 stumpy legs, slow moving
<1 mm

See gallery links on the right for some of the finest video clips on the Web of these cute critters!

Hunting for 'bears' in the backyard
The incredible water bear
Water bear video gallery I
Water bear video gallery II


jointed limbs; many groups e.g. crustaceans ('water fleas'), mites 


Go to arthropods overview: e.g. ostracods, copepods, water fleas, mites etc.

other Arthropods:
Insect stages

wide variety of forms


Go to insect stages overview: e.g. caddisfly larvae, dragonfly nymphs, water beetles, etc.
Note: This suite of pages with links hopefully gives a useful overview, but it's neither a formal identification guide nor comprehensive. It doesn't cover many larger pond organisms (>1mm. e.g. molluscs, sponges, jellyfish etc.). Simple keys to identify these larger freshwater invertebrates and plants (mosses, water weeds etc.) are widely available (see below).

Introductions to pond-life on Micscape

The smallest page on the web

Micscape resources on other freshwater groups:

Things that don't belong where they are - jellyfish, 'shrimps' and sponges only occur in the sea - or do they?

Freshwater jellyfish

Freshwater shells - a gallery of some commoner types

Hungry utrics - an intriguing look at the bladderwort (Utricalia), a carnivorous freshwater plant

Some printed resources to identify larger freshwater life (> ca. 1mm)

'Water animal identification keys' by J Eric Marson.
12 pages of simple illustrated keys. 4th edn 1968, reprinted 1998. Available from Northern Biological Supplies.

'A key to major groups of British freshwater invertebrates' by P S Croft.
47 pages with illustrated keys. Reprint from Field Studies, 1986. Available from the Field Studies Council.

'A guide to the study of freshwater biology' by J G Needham and P R Needham.
70+ pages with keys and many line drawings to major microscopic and macroscopic plants and animals.
Available e.g. from Amazon Books.

Acknowledgements: Many thanks to all the Micscape contributors whose articles this guide links to. For clarity their names are omitted in the links above.

Comments to the compilers Wim van Egmond and Dave Walker (who are amateur naturalists) are welcomed. All images in the 'Kit' are by Wim van Egmond.




Collecting tips



Insect stages 


An Introduction to Microscopy

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Published in Micscape Magazine November 2000.

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Micscape is the on-line monthly magazine of the Microscopy UK web
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All images Wim van Egmond