The Northern Fleet operated an oceangoing taskgroup, mostly consisting of a destroyer squadron with 7 Gnevny class DD (and Baku, a Leningrad class DL) transferred from other fleets in 1941/42, as well as three Uragan class sloops. These uh, let's say, technically integrated into convoy escort, although that was largely limited to the White Sea.
In mid-1944 the Northern Fleet received about a dozen ships on loan, including the battleship HMS Royal Sovereign, the light cruiser USS Milwaukee and a couple destroyers.
The Black Sea Fleet at the time had a single battleship and half a dozen mostly older cruisers as a main strike force which was used in coastal bombardment in the early stages. In 1943, following the loss of three destroyers, Stalin forbade operations of large ships without his express permission, which meant that that taskforce stayed in port for the most part. They still captured most of the Romanian fleet in 1944, integrating their destroyers subsequently.
The Pacific Fleet sorta operated roughly a destroyer squadron (similar to the Northern Fleet), reinforced in '45 by two cruisers built locally. They were mostly stripped of manpower though and not really active much.
Most ships were part of the Baltic Fleet confined to the inner Gulf of Finland. For most of the war only submarines slipped through the blockade into open waters to harass German shipping a bit.
