Aquarists at Blue Planet Aquarium in Cheshire Oaks issued an international lonely hearts ad for their partner-less puffer in the run-up to Valentine’s Day.

Shaun the sharpnose puffer fish lost his long-term mate last year and ever since staff have been on the lookout for a replacement female.

Initial enquiries failed to turn up any potential partners and now the aquarium is looking further afield in the hope of discovering a suitable mate.

Blue Planet Aquarium’s Stacy Adams said: “Sharpnose puffer fish are monogamous and tend to mate for life.

“Unfortunately Shaun’s partner died last year and, despite numerous enquiries, we’ve so far had no success in finding a replacement.

“We’re now contacting other aquariums across Europe to see if they can help, however if there is anyone out there who thinks they may be able to come to Shaun’s assistance then please do let us know,” she added.

Found throughout the USA and the Caribbean, the sharpnose puffer lives on reefs and among seagrass beds. Fully grown adults reach up to 22 centimetres across.

Although potentially deadly, puffers are usually extremely placid fish and only become dangerous if threatened or stressed.

Many of them also develop a close relationship with their keepers; coming to the top of their displays to be fed and to interact with their carers.

Pufferfish are famously able to inflate their bodies by using special muscles and valves to rapidly gulp in and retain water. They have no ribs so they can inflate up to three times their original size.

There are over 120 different species of puffer fish. Some have been known to puff up in the throat of a predator and thus choke and kill it.

There have even been observations of puffers gnawing their way out of the stomachs of dolphins and sharks.

As well as the ability to inflate themselves most puffer fish are also highly poisonous and there have been a number of reported fatalities among diners in Japan where pufferfish - known as fugu - is considered a delicacy.