Ghost Shrimp (Palaemonetes sp.)

Palaemonetes is basically a shrimp with the walls left out — see straight through to the gut, the beating heart, even the developing eggs on a berried female, no dissection required. That transparency has made it a staple in high school and college biology labs for decades, but in a home tank it's just as valuable as a cheap, tireless scavenger that'll eat anything that hits the substrate before it can rot.

Care level: Easy · Temperament: Peaceful · Max size: ~1.5" · Min tank: 5 gal · Diet: Omnivore, scavenger