Fish
Pipefish
Syngnathidae · also called pipefish, pipefishes
A pipefish is what you get if you take a seahorse and pull it straight. It shares the same bony-ringed body, the same toothless tube snout, and the same remarkable trick of male pregnancy, but instead of curling into a hook-tailed question mark, a pipefish stretches out long and thin and disguises itself as a strand of drifting seagrass, swaying gently in time with the current.
Overview
Pipefish are the family Syngnathidae, the same family as seahorses, found in seagrass beds, mangroves, and weedy reefs worldwide, with a few species living in fresh water. They suck tiny crustaceans through a narrow, jawless, tube-shaped snout, and swim slowly by rippling a single dorsal fin, better suited to threading through vegetation than fleeing a predator.
Camouflage and male pregnancy
Most pipefish are patterned and shaped to mimic seagrass or weed, some swaying side to side to match the movement of the current. As in seahorses, the female transfers her eggs to the male, who fertilises them and carries them — in a sealed brood pouch or glued to his skin, depending on species — until he releases fully formed young.
Status
Least Concern for many widespread species, but the wider Syngnathid family is under growing pressure from seagrass and mangrove loss, incidental bycatch in fine-mesh fishing nets, and collection alongside seahorses for traditional medicine and the aquarium trade.
Pipefish: common questions
Are pipefish related to seahorses?
Yes, closely. Pipefish and seahorses belong to the same family, Syngnathidae, and share several defining features, including a body armoured with bony rings instead of scales, a long tube-shaped snout with no biting jaws, tiny gill openings, and, most famously, a reproductive system in which the male carries the developing young rather than the female. The main visible difference is body shape, since a seahorse has curled its body into an upright, hook-tailed posture over its evolutionary history, while a pipefish has kept the ancestral long, straight, eel-like form.
How does male pregnancy work in pipefish?
During mating the female deposits her eggs onto or into a structure on the male's body, which depending on the species may be a fully sealed brood pouch on the tail or underside, similar to a seahorse's, or simply an open patch of specialised skin the eggs are glued to. The male fertilises the eggs as they are transferred and then provides oxygen and, in pouch-brooding species, additional nutrients and protection for several weeks, until he releases a batch of fully formed, independent miniature pipefish, essentially performing every parental duty other than producing the eggs themselves.
Why does a pipefish sway back and forth while swimming?
The gentle side-to-side swaying seen in many pipefish, particularly species that live among seagrass or floating weed, is thought to be a form of camouflage in motion, mimicking the way a real strand of grass or weed moves as it is pushed by waves or current. Because a pipefish is already coloured and shaped to resemble vegetation, moving in the same rhythm as its surroundings helps it blend in even while it is actively swimming, rather than only when it is holding still, making it harder for a predator scanning the weed bed to pick it out.
Can pipefish be kept in a home aquarium?
Some species can, but they are considered a specialist and challenging fish rather than a beginner choice, for much the same reasons as seahorses. Pipefish need a very stable, mature, gently flowing tank, are picky and slow feeders that generally require live or frozen small foods such as copepods, mysid shrimp, or baby brine shrimp rather than flake, and do poorly with fast or aggressive tankmates that outcompete them for food. Because of the pressures on wild populations, prospective keepers are encouraged to seek captive-bred pipefish where available rather than wild-caught individuals.