Staff at the Blue Reef Aquarium in Portsmouth are celebrating after their male pipefish gave birth to hundreds of babies.
Male pipefish incubate the eggs and give birth to the young. Rows of eggs are laid by the female on to a special pad on the male's belly, and here the eggs develop.
Keeper Lindsay Holloway said: "Greater pipefish are among the largest species of pipefish found in UK waters and they can grow to be up to 45cm in length.
"We knew the fathers were pregnant but itís always a great feeling to come in and find their display filled with dozens of tiny babies.
"When they hatch the babies are identical miniature versions of their parents, only a fraction of the size."
The young are born free swimming with relatively little or no yolk sac, and begin feeding immediately. From the time they hatch they are totally independent.
Pipefish feed on small crustaceans such as mysid shrimps and tiny creatures called copepods. An adult greater pipefish needs to eat several hundred tiny shrimps in one day.
UK waters are home to six different species of pipefish and two species of seahorse.
In the wild, pipefish live in relatively shallow waters over sandy seabeds or rough ground among seaweed and eel grasses.
Like seahorses, pipefish are extremely slow moving fish and have developed a hard, armour-like outer skeleton to help protect them against would-be predators.
They are often present in rockpools although their seaweed-like bodies mean they are well camouflaged and easily overlooked.