There are thousands of species of jellyfish around the world, but only six are common in UK waters.

You may catch a glimpse of these jellyfish in UK waters during various times of the year.

While there aren't any jellyfish in UK waters that are as dangerous as the box jellyfish, which is found in Australia, there are some that can give you a nasty sting.

It is important to remain cautious when swimming in the ocean and avoid jellyfish where possible.

Vets also warn dog owners to keep their four-legged friends away from them at all times, even if the jellyfish is dead as they still have the ability to sting for several weeks.

Jellyfish found in UK waters - are any of them dangerous?

The six jellyfish commonly found in UK waters are:

Moon jellyfish

Moon jellyfish are the most common species found in UK waters.Moon jellyfish are the most common species found in UK waters. (Image: Getty Images)

The Moon jellyfish is the "most common" jellyfish found in UK seas, according to The Wildlife Trusts, usually appearing during the winter months.

It resembles a moon in appearance and is roughly the size of a dinner plate with four distinctive circles on its white milky dome. It also has short, delicate tentacles.

It lives for around six months and can usually be seen floating just below the surface of the water.

Barrel jellyfish

The barrel jellyfish is one of the largest found in UK waters, the Wildlife Trusts continued.

They are usually found washed up on UK beaches in May and June.

They are translucent with a huge mushroom shaped bell, with a violet fringe and eight frilly tentacles below.

Lion's mane jellyfish

Lion's man jellyfish are one of the larger species found in UK waters.Lion's man jellyfish are one of the larger species found in UK waters. (Image: Robert la Salle/Getty Images)

The lion's mane is also one of the larger jellyfish found in UK waters, measuring up to two metres in diameter, BBC's Countryfile explains.

"Also sometimes known as the giant jellyfish its longer tentacles reach tens of metres in length," Countryfile adds.

It is a translucent brown to reddish jellyfish with a thick mane of hundreds of long hair-like tentacles. They also have thick, frilled oral arms under the bell, mostly brownish in colour.

Blue jellyfish

The blue jellyfish is often confused with the lion's mane as there are very similar in appearance.

Countryfile says: "A similar shape and size to the lion's jellyfish, the blue jellyfish is translucent when young before maturing into a vibrant blue/purple colour. It can measure up to 30cm across."

It tends to appear in the UK in late summer and autumn.

Dangerous jellyfish in the UK

While most of the jellyfish common in UK waters aren't dangerous, there are a few that can leave you with a nasty sting:

Compass jellyfish

Compass jellyfish usually wash up on UK shores during summer.Compass jellyfish usually wash up on UK shores during summer. (Image: Getty Images/iStockphoto)

Compass jellyfish are a translucent yellowish-white colour with brown markings resembling a compass.

They also have a bunch of frilled oral arms below the bell, according to The Wildlife Trusts.

These jellyfish usually wash up on UK shores during summer months.

BBC's Countryfile adds: "So be careful when walking barefoot along the shoreline as this common species can give a nasty sting."

Mauve stinger jellyfish

Mauve stinger jellyfish are toxic with a powerful sting.Mauve stinger jellyfish are toxic with a powerful sting. (Image: Getty Images/iStockphoto)

BBC's Countyfile says: "A toxic jellyfish with a powerful sting, the mauve stinger jellyfish is one you want to avoid while swimming."

The mauve stinger jellyfish is "fairly uncommon" in UK waters as they tend to "float further out at sea or in warmer waters".

This jellyfish has a bright purple/yellow coloured dome covered in orange warts, while its thin tentacles hang down from around the bell and can reach a maximum of three metres.

What does a jellyfish sting look like?

"Jellyfish stings will leave a rash and can be quite painful with a burning sensation," BBC's Countryfile explains

"The sting tends to be line of red, raised welts or blisters which will leave an itchy rash."

How to treat a jellyfish sting?

Jellyfish found in the UK don't tend to be poisonous, unlike the Box jellyfish in Australia which injects a poison as it stings.

However, a jellyfish sting can still be painful and Countryfile said to take caution when swimming in the sea and avoid areas where they are swarming.

If you are stung by a jellyfish, the NHS says to:

  • Rinse the affected area with seawater (not fresh water)
  • Remove any spines from the skin (using tweezers or edge of a bank card)
  • Soak the area in very warm water (as hot as can be tolerated) for at least 30 minutes
  • Take painkillers (like paracetamol or ibuprofen)

You may need to visit the minor injuries unit if you've been stung and:

  • Have severe pain that is not going away
  • You've been stung on your mouth, throat or near your eyes

Vet issues warning to keep dogs away from jellyfish

Oakhill Veterinary Centre has warned dog owners to keep their four-legged friends away from jellyfish even dead ones that have washed up on the beach.

The vets said: "The tentacles of jellyfish have nematocysts, which are the cells that cause the stinging sensation.

"You may approach them to have a closer look, but you shouldn’t touch them and neither should your dog! If you see any jellyfish you should put your dog on a lead to avoid them touching them.

"Although the fur on most dogs offers a layer of protection, they can be just as vulnerable to stings on lightly furred areas such as the face, feet, and abdomen.

"They are also at risk for stings inside their mouths if they attempt to pick up a jellyfish with their mouths.

"Washed-up jellyfish may be dead, but they still have the ability to sting for several weeks."

Signs your dog has been stung by a jellyfish

Oakhill Vets said it is "unlikely" that your dog will die from a jellyfish sting, or from licking or swallowing one but it may cause an array of symptoms including:

  • Nausea, retching and vomiting
  • Excessive drooling
  • Swelling
  • Licking affected area
  • Difficulty breathing
  • Quiet and lethargic
  • Itching
  • Muscle cramps

Best beaches in the UK

These symptoms may begin to occur anywhere from two minutes to three hours after the sting.

The veterinary centre added: "The recovery time for dogs stung by a jellyfish ranges from two to 48 hours and most dogs usually recover with no side effects."

What should you do if your dog is stung by a jellyfish?

"A jellyfish sting can be very painful, especially to your dog," Oakhill Vets continued.

If you think your dog has been stung the vets recommend you "remove any stingers and stop the chemical reactions".

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To do this pull the remaining tentacles off with a stick or towel being sure to avoid rubbing them or coming in to contact with them yourself.

The Vets added: "Never rub the injured area with sand and always clean it with sea water rather than fresh water."

Once you have done that, contact your local vet "straight away".