Have you heard of Ecospheres? So, this was a gift to my lab from a member who left recently. They are a completely self contained ecosystem with sea water, algae, phytoplankton, and you can see at the bottom 4 tiny brine shrimp. The only thing it needs is light! Pretty neat, and they'll continue to coexist for about 2-5 years according to the manual. The shrimp will never reproduce so the lifespan of the shrimp translates into the lifetime of the Ecosphere.
And, what kind of nerdy lab would we be if we didn't name them appropriately after the Teenage Mutant Ninja Turtles? (or the famous Renaissance artists if you want to go with that)