How to Identify Jellyfish

There are over 200 jellyfish species over the world, and they all have differences in their physical appearances. Familiarizing yourself with key characteristics of the jellyfish is important to being able to narrow the search down to identify the exact species of the jellyfish, and make it less painful in the process. Before trying to encounter a jellyfish make sure to look at the warnings listed below.


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    Locate the general area where the jellyfish is . There are many types of jellyfish in the world, but most can only survive in certain climates.
    • To find the general area, ask yourself these questions:
      • What is the name of the body of water the jellyfish in?
      • What is the closest city?
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    Pay attention to what time of year it is. Many jellyfish migrate with respects to currents, and get pushed with weather patterns. So, when trying to identify a jellyfish, knowing the time of year can be helpful.
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    Pay attention to the environment. The surroundings where you encounter a jellyfish can help with identification.
    • Ask yourself these questions:
      • Was it near the surface of the body of water?
      • Were you scuba diving in deep water?
      • Were there other living things around the jellyfish?
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    Take note of the color and other markings on the jellyfish. Jellyfish have a variety of colors and patterns, but start by noticing the main base color. Notice if the jellyfish is one solid base color or if it has other colors on it too. If it has more than one color, notice how the different colors are arranged and if this pattern extends to the tentacles.
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    Look at the tentacles and the oral arms. On the body of a jellyfish, the oral arms extend from the middle and the tentacles are around the edges. This is important because different species of jellyfish can have varying combinations of both.
    • Try to answer these questions:
      • Approximately how many are there?
      • How long are they?
      • Are they all the same size?
      • How are they arranged on the jellyfish?
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    Look at the shape of the jellyfish's body. It will be in the shape of either a bell or more spread out like the top of an umbrella.
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    Try to estimate the distance across the top of the body.This distance can range from just a few centimeters up to around three meters. Try comparing the jellyfish’s size to something in your mind to get an estimate. Is it the size of a grape, an apple, or a watermelon?
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    Take the information gathered in the steps above and identify the jellyfish. To do this you can use an online source[1] . Or, check you local library for printed reference materials.


  • If stung, scrape the skin with a credit card, safety razor or knife edge to remove remaining nematocysts
  • An antihistamine, such as diphenhydramine(Benadryl) may help reduce skin irritation.
  • If trying to observe a jellyfish try not to remain still to avoid startling the jellyfish


  • Never try to approach a jellyfish, their stings can be deadly.
  • If stung by a jellyfish, do not apply urine, alcohol, fresh or cold water. Apply vinegar or sea water and seek medical attention.[2]
  • Do not go scuba diving without being properly trained, proper equipment, and somebody with you.

Sources and Citations

  • Authors: J. David Whitaker, Dr. Rachael King and David Knott. Title: Sea Science .Publisher: South Carolina DNR, Marine Resource Division.
  • Authors: Williamson JA, Fenner PJ, Burnett JW, Rifkin J. Title: Venomous and poisonous marine animals: a medical and biological handbook. Publisher:Sydney: New South Wales University Press, 1996.
  • Authors: Perkins RA, Morgan SS. Title: Poisoning, envenomation, and trauma from marine creatures. Publisher: National Institutes of Health, US National Library of Medicine.
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Categories: Wildlife