Are my eyes bigger than my... tank?

So I bought a Fluval Spec V for my first tank. I have no experience fishkeeping, so this is all brand new to me. I'd like to have inverts and fish. I want snails and shrimp, and I'm kind of undecided on fish still.

My questions is: am I over doing it for the tank size? Is it okay to have a snail or two, a few shrimp, and some fish (for the hypothetical situation's sake, let's go with a betta) all in a 5 gal tank together?