The creatures are under threat in the wild, the aquarium says
Staff at a Cheshire aquarium hope a new collection of South American seahorses will help boost future numbers of the threatened species.
Four Brazilian seahorses have gone on display at the Blue Planet Aquarium in Ellesmere Port.
Staff hope to create a breeding colony with the creatures, which will be joined by another four in a few weeks.
In the wild, most species of seahorse are under threat from a variety of sources, the aquarium said.
Brazilian seahorses are found among shallow coral reefs and sea grass beds from the coast of Florida down as far as Brazil.
Threats include a loss of habitat, pollution and the souvenir trade.
Traditional Far East medicine is also believed to account for the deaths of more than 20 million seahorses annually, the aquarium said.
Tom Cornwell, Blue Planet's exhibits manager, said: "Seahorses are always among the most popular displays with visitors and the new arrivals are certainly proving a big attraction.
"As well as being among the most beautiful - males are often bright orange and females yellow - this particular species is also among the largest with full grown adults reaching lengths of up to 20 centimetres.
"We're hoping that some of the slender seahorses may be pregnant and that we will soon be looking after a new generation of these fascinating creatures."