The shallow silty flats along Hobart's Sandy Bay and Battery Point foreshore are home to one of the rarest fish on Earth. The spotted handfish is a small anglerfish relative that walks across the seabed on hand-like fins. Once common along south-east Tasmania, it now survives in fewer than ten small colonies in the Derwent estuary, plus a population discovered in the D'Entrecasteaux Channel in 2015; the Derwent Estuary Program notes it was the first marine fish listed as endangered under the EPBC Act, and CSIRO notes it was the first marine fish listed as critically endangered on the IUCN Red List.

RACT's dive guide mentions shore diving along Sandy Bay and around to Battery Point as a chance to see one, and Go Dive Tasmania runs guided handfish dives in Sandy Bay at 5-14 m. The environment is not scenic in the conventional sense – silt, sand, scattered shells and debris, and the stalked ascidians known as sea tulips – and underwater photographers describe it as bitterly cold, with less than 2 m of visibility. The reward is the handfish itself, as well as stargazers, pipefish, sea pens and other sand-dwellers.

Handfish lay their eggs on sea tulips and other upright structures in September and October; the invasive Northern Pacific seastar has devastated sea tulips, and scallop dredging and swing moorings have also destroyed habitat. CSIRO and partners now plant artificial spawning habitat, run captive breeding and promote eco-moorings. Divers can help by never touching fish, eggs or spawning structures, keeping off the bottom, and reporting sightings.

This is a specialist dive for patient critter enthusiasts.

Sandy Bay and Battery Point are Hobart inner suburbs, 5-10 minutes from the CBD along Sandy Bay Road. Public beaches such as Long Beach and Nutgrove Beach have parking, toilets and easy walk-in entries. Go Dive Tasmania runs guided handfish shore dives in Sandy Bay (5-14 m); operators and researchers ask that precise locations not be published, so the best approach is to dive with a guide who knows the colonies and the rules.

Keep clear of marinas, moorings and the yacht-club areas.

The Derwent estuary is sheltered from ocean swell, but strong northerly or southerly winds blow along its length and raise a short, steep chop; the Marine Life Network notes the region can become very rough in gales, even in the river. Visibility is the limiting factor: it is usually low (1-5 m) and worst after rain, when the Derwent's tannin-stained, silty floodwater spreads through the estuary. Dive after a dry spell, on a high or flood tide that brings in clearer marine water.

There is a noticeable but generally mild tidal flow. Diving is possible year-round; winter water is cold (9-11 °C).

Enter with the guide, descend slowly to the silty sand at 8-12 m without stirring the bottom, and search slowly in a line along a depth contour. When a handfish is found, stop, settle a metre away, watch or photograph briefly without lights in its face, and move on without touching the bottom.

Go Dive Tasmania – guided 'Handfish – Sandy Bay' shore dives (5-14 m, all certified divers); The Dive Shop Hobart – local knowledge; research dives by CSIRO/IMAS.