If you don't have anything that would give you some current(i.e. powerhead, canister filter, hang-on filter, overflow and sump) you really need to get one. You don't want stagnant water in your tank, as many opportunistic organisms will breed in these places that you don't want. If you don't have water moving right now, I urge you to go and get at least one good powerhead to get the water moving.