Macroinvertebrates” by Bruce C Chessman. Marine & Freshwater Research 2003, 54, 95-103. NR NR NR Green, white or black. Swims with smooth motion. Teardrop shape, jerking movement. Swims with a jerk using antennae. Seed Shrimp Copepod Water Flea Flattened Shell with small hump. Spiral Shell, opening on the left. Spiral Shell, opening on the ...