Seahorses gone straight, with radical ideas on parenthood - Paul Naylor reports
BUILT-IN OUTBOARD Pipefish are fairly slow-moving and rely on body armour and camouflage to avoid being eaten. Their shape and colour allows them to blend in with seaweed or eel-grass. They swim with their vibrating dorsal fin acting like a propeller, or by using snake-like wriggling movements of their whole body.
HE'S PREGNANT! Good paternal care is common in inshore fish, but pipefish take this to the extreme, with males actually brooding the eggs. Folds of skin on the father's belly can form a special brood pouch, though it is simply a groove in some species. Youngsters stay in here until they are fully-formed miniature adults but, even then, might dive back in when danger looms.
LASTING LOCKJAW Pipefish have a long tubular mouth, formed by jaws that are permanently locked together. There are no teeth, and the mouth acts like a syringe, sucking in tiny planktonic crustaceans or fish fry, but usually only after the prey has been carefully scrutinised. They are notoriously fussy feeders, blowing food back out if it is not up to scratch.
SNAKE MISTAKE Several species of pipefish are found in British waters. The largest, the snake pipefish (pictured), can reach 60cm. They are occasionally seen in open water, where their size, distinctive colouration (orange with dark bands) and virtual lack of a tail fin can lead to confusion with sea snakes - which are very rare in our waters.
SEA DRAGONS In essence, pipefish are straightened out, slender seahorses. Like seahorses, they have no scales and their bodies are instead protected by a series of bony rings that encircle them from just behind the head right down to the tail. This armour gives some species, such as the greater pipefish, a very stiff, dragon-like appearance.
SWINGERS Reversing the usual roles in the animal world, the female of some pipefish species makes all the running during courtship. During mating she lays her eggs into the male's pouch, where he fertilises them before starting his duty of care. Females can leave eggs with several males but the males join in the easy-going life too, often brooding the eggs of more than one female at the same time.