Seahorses & Relatives > Biology of Pipefishes, Pipehorses and Seadragons

Biology of Pipefishes, Pipehorses & Seadragons

Seahorses are members of the family Syngnathidae, which includes true pipefishes (e.g. genera Nerophis and Syngnathus), the pipehorses (genera Solegnathus and Acentronura), and the seadragons (two genera with one species each, Phycodurus eques and Phyllopteryx taeniolatus). Sea moths, ghost pipefishes, trumpetfishes, flute mouths, snipe fishes and razor fishes are other unusual fish believed to be related to the syngnathids.

Pipefishes

A reasonable taxonomy is in place for most of the 200 or so pipefish species (in perhaps 35 genera), especially those found in the Indo-Pacific. Pipefishes have a much wider latitudinal distribution than seahorses, and are even found in freshwater.

All male pipefishes undertake egg brooding. The male brood pouch varies among pipefish genera, from simple ventral gluing (e.g. Nerophis, Entelurus), to walls protecting the eggs (e.g. Syngnathoides, Corythoichthys), to fully enclosed "zipped" pouches (e.g. Syngnathus). Collaborative genetic work indicates that this continuum of care probably reflects an evolutionary gradient, culminating in the fully sealed pouch of the seahorses (Hippocampus).

Few pipefish species have been studied, and none of the most exploited species are well understood. In general, however, pipefishes are like seahorses in having sparse distributions, relatively low mobility, low fecundity, and lengthy parental care. In their behaviour and ecology, pipefishes fall into two major groupings: some pipefishes are similar to seahorses in forming monogamous pair bonds and are rigidly site faithful (e.g. Corythoichthys intestinalis; Filicampus tigris) while other species are polygamous, and range more widely (e.g. Nerophis ophidion, Syngnathus typhle); the latter appear to be sex-role reversed, with females competing most actively for access to mates

Pipehorses

Certain genera of pipefishes are commonly known by the vague designation of pipehorses, largely because they appear to be intermediate in form between seahorses and pipefishes. In general, the pipehorse's head is angled slightly toward its trunk, and it has an elongated body with a grasping or coiling tail. The dwarf pipehorse (Acentronura tentaculata) is well camouflaged to match its habitat of shallow sandflats.

Pipehorses of the genus Solegnathus are the most valuable syngnathid in traditional Chinese medicine.

Sea dragons

The two genera of sea dragons each include one species, both endemic to Australian waters. The leafy sea dragon (Phycodurus eques) and the weedy or common sea dragon (Phyllopteryx taeniolatus) may reach up to 45 cm in length. They have elaborate, permanent leaf-like appendages which help to camouflage them among seaweed. Sea dragon males may incubate up to 250 eggs at a time on their tails. Small numbers of sea dragons are sold as ornamental fishes, most commonly to public aquariums. These quirky animals are not, however, used in traditional Chinese medicine, despite references to them by practitioners. This is because the name "sea dragon" in TCM is a literal translation of the Chinese name (hai long), meaning a pipehorse, or sometimes a pipefish, and does not refer to those fishes called sea dragons in English.

Visit the Dragon Search website to learn more about these beautiful fish.