The red pipefish (Notiocampus ruber) is a rare relative of seahorses and seadragons found only in Australia.
While the species occurs across southern Australia from Western Australia to New South Wales, its incredible camouflage means until now only one person had ever photographed it in the wild.
In Gamay (Botany Bay) it has been observed hiding among feathery red algae, but elsewhere the red pipefish has been recorded on rocky reefs. Its colour and slender body allow it to disappear almost completely against its surroundings.
For decades, scientists have wondered how these elusive creatures carry their eggs. Our new photographs and research , published in the Journal of Fish Biology, finally provide an answer.
A lucky sighting
One of us (Andrew) regularly dives the popular Sydney sites The Leap and The Steps at Kurnell, Gamay (Botany Bay), where he documents seahorses, pygmy pipehorses, seadragons and other related sealife.
Andrew had briefly seen a red pipefish twice before. However, he struck gold when he spotted one at Kurnell in April 2021. He kept tabs on this individual, spotting it almost weekly until January 2022.
During that time it was joined by two more red pipefish. When all three were sighted in November 2021, one was a brooding male carrying eggs on his trunk.
Tails or trunks?
While pipefishes and seahorses are famous for male pregnancy, the family is split by how the males carry their young. Many pipefish - and all seahorses - are "tail brooders", carrying eggs on the tail in pouches.
Another group of pipefish, the "trunk brooders", carry eggs exposed directly on the belly. However, scientists have suspected the red pipefish was a tail brooder since 1979 based on the structure of its body. However, without a living male to study the theory remained unproven.
Andrew's photographs from his November 2021 dives at Kurnell finally provided the proof. They clearly show a male carrying large eggs attached directly to the belly - confirming the species as a trunk-brooder and placing it in an ancient group of pipefishes that lack pouches entirely.
Interestingly, the data suggest this Australian fish may be a long-lost relative of species found as far away as the North Atlantic, despite the vast geographical separation.
Finding such a rare fish in the well-dived waters of Gamay is a reminder that major biological secrets are still hiding in plain sight.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
