Both species can reach the same length, but the latter tends to be bigger and heavier. Those seen in UK waters can exceed 3m in length and weigh well over a tonne!
They are an exceedingly odd-looking fish, resembling a big head with long fins sticking out. They are flat, circular, with no discernible tail. They are almost as wide as they are long with two long fins, one at the top (dorsal fin) and one underneath (anal fin) which function like rudders on a ship to steer. Additionally, it has two smaller pectoral fins used to propel them along.
The best time to see these creatures in Cornwall is in the warmer summer months between June and September. Come and join us for an opportunity to see a sunfish!
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The sunfish is named as such due to their frequent basking behaviour in the sunlit surface water – thought to be necessary to raise their body temperature after diving to deep, cold water to feed.
The sunfish’s primary prey is jellyfish and is immune to the nastiest of stings to hunt this prey, even that of the infamous Portuguese man-of-war.
Sightings of sunfish in Cornish waters are now considered regular where they were once rare. This is attributed to the increasing numbers of jellyfish, associated with rising water temperatures. While wallowing about in the shallows, they are often spotted ‘finning’ whereby the large dorsal fin pokes above the surface. From a distance, it is easy to mistake for a shark or a cetacean. They are often spotted making large splashes with their fins and have been seen breaching 3 feet out of the water!