The Fish Bommies sit at the deep, seaward end of the gutter that leads up to Fish Rock Cave's deep entrance, on the south-eastern corner of the island at 28 to 32 metres. Rather than a single bommie, the site is a scatter of semi-trailer-sized boulders that have tumbled off the rock over geological time, creating a maze of overhangs, crevices and swim-throughs on the sand. It is one of the better spots at Fish Rock for close encounters with juvenile grey nurse sharks as well as full-grown adults up to three metres, which use the boulder gaps as much as the open gutters, and the structure also holds a strong population of ornate and spotted wobbegongs tucked under the ledges.

Black coral trees grow from several of the larger boulders, and sponges and gorgonians cover the exposed faces, giving the site good colour for a spot this deep. Fish and invertebrate life is dense: bullseyes and kingfish move through the gaps, loggerhead and green turtles use the boulders for rest stops, and moray eels, octopus and nudibranchs occupy the smaller cracks. Because the site sits deeper than the cave and Shark Gutters, it is usually offered as a second dive for groups who want a change of scenery and a chance at grey nurse sharks away from the busier gutter mooring, and it works well linked with a swim up to the deep cave entrance to finish.

The depth and the maze-like boulder terrain mean it suits divers who are comfortable navigating without a fixed reef line and who can manage a 28-32 m profile with a sensible reserve, rather than newly certified divers, but it rewards that experience with one of the more overlooked but genuinely excellent corners of the Fish Rock complex.

All Fish Rock sites are boat access only, departing from the boat ramp/marina at South West Rocks (Fish Rock Dive Centre and South West Rocks Dive Centre both operate from the town, 4 New Entrance Road area). The run out to Fish Rock, off Smoky Cape about 2 km offshore, takes roughly 15-25 minutes depending on the vessel and sea state. Boats moor directly on the site — there is a southern mooring near the cave/shark gutters and a northern mooring near The Pinnacle — so there is no surface swim; divers descend the mooring line straight onto the reef.

Double boat dive trips (two dives, roughly 5 hours total) run most days when weather allows; book ahead as Fish Rock is a signature Australian dive and trips fill, especially in the May-November grey nurse season.

Fish Rock sits in open ocean off Smoky Cape with no shelter, so trips are cancelled on any strong onshore swell or wind over about 20 knots; operators want under 1.5-2 m swell to run safely. The site is affected by a north-setting current for roughly 80% of the time, and it can run strong enough to make the cave and Pinnacle undiveable — the best conditions are the day after the current has dropped out or during a brief slack. Visibility is usually 15-30 m and can be exceptional (30-40 m) inside the cave itself; it drops after east coast lows and heavy rain runoff from the Macleay River.

Grey nurse sharks are present year-round but peak May-September, with leopard (zebra) sharks more likely February-April. Dived year-round; winter mornings before the sea breeze are usually calmest.

Descend the southern mooring and follow the main gutter out to its deeper end where semi-trailer-sized boulders form the Fish Bommies at around 28-32 m. Work through the gaps and overhangs between boulders looking for wobbegongs and juvenile grey nurse sharks, then rise back up the gutter toward the cave's deep entrance to finish the dive.

Fish Rock Dive Centre (South West Rocks) — double boat dives most days, year-round; South West Rocks Dive Centre — daily boat trips to Fish Rock.