A deep-ocean mooring system was deployed 100 m away from an active hydrothermal vent over the Southwest Indian Ridge (SWIR), where the water depth is about 2,800 m. One year of data on ocean temperature 50 m away from the ocean floor and on velocities at four levels (44 m, 40 m, 36 m, and 32 m away from the ocean floor) were collected by the mooring system. Multiple-scale variations were extracted from these data: seasonal, tidal, super-tidal, and eddy scales. The semidiurnal tide was the strongest tidal signal among all the tidal constituents in both currents and temperature. With the multiple-scale variation presented in the data, a new method was developed to decompose the data into five parts in terms of temporal scales: time-mean, seasonal, tidal, super-tidal, and eddy. It was shown that both eddy and tidal heat (momentum) fluxes were characterized by variation in the bottom topography: the tidal fluxes of heat and momentum in the along-isobath direction were much stronger than those in the cross-isobath direction. For the heat flux, eddy heat flux was stronger than tidal heat flux in the cross-isobath direction, while eddy heat flux was weaker in the along-isobath direction. For the momentum flux, the eddy momentum flux was weaker than tidal momentum flux in both directions. The eddy momentum fluxes at the four levels had a good relationship with the magnitude of mean currents: it increased with the mean current in an exponential relationship.