The Special Space Surprise Starfleets, as their name implies, were specialized warfleets in Opposition Navy as well as specializing in attacking Human Allies fleets with surprise attacks as the Remnant's Stealth Attack Starfleets worked with the S.S.S.S. on a few situations during the Human-Alien Conflict.
When the Proclaimation of the Revived Species was proposed by the High Overlord of the Opposition, the S.S.S.S. was formed as the Opposition Surprise Starfleets but was later changed to Special Space Surprise Starfleets just before the Human-Alien Conflict broke out between the Human Allies and Alien Axis forces. This branch of the Opposition Navy consisted of over a hundred fleets, possibly surpassing a thousand by 200 BBY.