Take a look at this.
"The EcoSphere is the result of technology developed by scientists at NASA's Jet Propulsion Laboratory. NASA was researching self-contained communities for space explorers to live in during long-term space flights. Out of this research came the EcoSphere - an ecosystem of animal and plant life in perfect balance."
Pretty much, it's an entire, albeit very small, ecosystem in a glass ball. Each EcoSphere contains microscopic organisms, bacteria, shrimp, algae, etc. inside filtered seawater. It's also self-sustainable, so there's no need to feed or clean. Just...observe.
How delightful! This is more than an office desk decoration, it's an entire world. They're start at about $79 and go up to $489.