Upside-down Pipefish

Heraldia nocturna

Upside-down Pipefish (Heraldia nocturna)

It can be recognised by its very large caudal fin with incised membrane, and raised body ridges along the body.

There are two distinct forms. The east coast form is recorded from northern to southern New South Wales. It is dark brown to black with or without pale blotches. The south coast form is a mottled yellow-brown with light markings and a smaller caudal fin.

It lives in protected bays and estuaries down to a depth of about 20m, where it is usually seen in pairs in caves and under ledges. It is often seen swimming upside-down, hence the common name.

I have seen them on the west side of Bare Island, Sydney.