well, if it were above, you could return the water to the tank via siphon, and therefore continuously repopulate your pod population in your main tank. That way, you could have the mandarinfish in your display tank, and the pods in the fuge would reproduce, and therefore, you'd basically have an unlimited supply of pods...
If you put the mandarinfish in the same tank where the entire pod population is, the fish would eat all of the pods...