My wife has a 30 l shrimp only tank. They are cherry shrimp (neocaridina davidi). She bought reds and blues which created chocolate when they bred. They breed so quickly we frequently give the local MA a bunch for free. I've volunteered for darkness (my betta) to go in with them for some population control but it hasn't happened yet.
I think you should all go out and buy a shrimp tank now. Go on. *nudge, nudge*