Look inside the outlet and see how many wires are in there, and what colors they are. (Ignore any bare ground wire.)
If there are 3 wires, black-white-red or 2 blacks + 1 white, great! You should be easily able to change this to a 110V circuit (in fact, 2 separate 110V circuits). There will be 110V between the white wire and each black or red wire. (Between the 2 blacks or the black & red wires there is 220V; that was what the previous circuit used.) You should also change the double-pole breaker that this circuit was connected to into a pair of single-pole breakers.
If there are only 2 wires (black & white), you can still make it into a 110V circuit. Just wire those 2 wires into the new 110V receptacle, and then in the breaker box change the wiring so the black wire goes to a single-pole breaker, and the white goes to the neutral bus.
You don't need an electrician, if you think you can do the described changes. If you're not sure, be safe and hire an expert.
Reviewing, this is based on the assumption that you are planning on REPLACING the hot-tub circuit with a fountain one. If you want to both keep the hot tub 220V circuit and add a 110V circuit to it, tell us. And tell us how many & what color wires are there.
(In many locations, the code requires that a hot tub be on its' own, exclusive circuit. So tapping into that for a 110V fountain circuit would NOT be code-legal. In which case, you would have to run a separate cable back to the breaker box (or a different outlet) for this fountain circuit.)