Here is a variety of invertebrates, including some macro and microscopic animals.
Hydra with a Bud 
Vorticella 
Aquatic Segmented Worm 
Daphnia 
Daphnia 
Daphnia 
Aquatic Segmented Worm 
Aquatic Segmented Worm 
Aquatic Segmented Worm 
Aquatic Flatworm 
Aquatic Flatworm 
Aquatic Flatworm 
Aquatic Flatworm 
Aquatic Segmented Worm 
Aquatic Round Worm 
Head of Aquatic Insect Larva 
Aquatic Insect Larva 
Jellyfish 
Jellyfish 
Jellyfish 
Jellyfish 
Hyrda – Fully Expanded 
Two Hydras – Bottom One Has Just Eaten 
Hydra 
Beetles Mating 
Sea Anemone 
Sea Anemone 
Dragonflies Mating