  We compute fourth sound for superfluids dual to a charged scalar and a gauge
field in an AdS_4 background. For holographic superfluids with condensates that
have a large scaling dimension (greater than approximately two), we find that
fourth sound approaches first sound at low temperatures. For condensates that a
have a small scaling dimension it exhibits non-conformal behavior at low
temperatures which may be tied to the non-conformal behavior of the order
parameter of the superfluid. We show that by introducing an appropriate scalar
potential, conformal invariance can be enforced at low temperatures.
