A three foot fish “like a giant swimming head” has been spotted off the coast.

Ian Rudge was anchored and fishing about one mile south west of Shoreham Harbour on Saturday when he saw a fin above the water.

Sussex Wildlife Trust experts have confirmed Ian’s pictures are of a sunfish.

Ian said: “The fish approached our boat travelling west at a leisurely pace and passed us by being totally unperturbed.

“When it was close enough we collectively identified it as a small sunfish approximately two to three feet in length which we watched for five to ten minutes as it proceeded on its journey.”

Ocean sunfish are the second largest bony fish on the planetOcean sunfish are the second largest bony fish on the planet (Image: Ian Rudge)

Sunfish, which are occasionally seen in British waters in summer, are listed as vulnerable by the International Union for Conservation of Nature (IUCN).

They are the second largest bony fish on the planet.

The creatures come to the seas here to feast on jellyfish and have previously been spotted near the Rampion windfarm off the coast of Brighton.

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A Sussex Wildlife Trust spokeswoman said: “The ocean sunfish is an odd looking fish. It is huge, flat and circular - looking pretty much like a giant swimming head. Instead of a tail, it has a stiff fringe of skin (called a clavus), which it can move to act like a ship's rudder.

“It also has two small pectoral fins and an elongated dorsal fin and anal fin that look a bit like wings.”

Sunfish have a wide rangeSunfish have a wide range (Image: Ian Rudge)

Sunfish have a wide range and are found across tropical and temperate waters. They have been seen across the length of the Atlantic from Iceland to Chile.

In the UK, they're most often seen in summer months and are an increasingly common visitor to southern and western waters around the country.

People who spot sunfish are urged to report sightings to their local wildlife trust.

If you spot a sunfish at sea, advice is to maintain a distance of 100m and put the engine into neutral if any closer to avoid propeller injury.