The blue jellyfish have become more common in Guernsey since 2009
The blue coloured Cyanea Lamarckii jellyfish has been a more common sight on Guernsey shoreline in recent years.
In May 2009 a large number were sighted in Havelet Bay and in June 2010 many were seen off Guernsey's west and south coasts.
Marine life educator Richard Lord explained that the jellyfish's stings were not that severe.
He said: "I think young children are more vulnerable [to the sting] as they have thinner skin."
The jellyfish can be big as 30cm across though most are closer to 20cm
Also known as Bluefire Jellyfish, Richard said they grow up to 30cm (11.8in) in diameter however most are smaller than this.
Like all jellyfish, he explained, these blue creatures have limited control over their movements and so wash up on beaches depending on the prevailing wind.
Though the blue jellyfish do have a sting, Richard said it was "probably the weakest of the ones that come on our shore", adding the ones to be more wary of are the Compass Jellyfish which has a brown bell with V shaped markings.
If stung by the blue jellyfish Richard said the best thing to do was to: "Flush it [the stung area] with cold water and you can use antihistamines, but don't rub it."