Fat-armed 
            jellyfish 
            Catostylus sp. 
            Family Catosylidae 
            updated 
            Sep 2025
             
            Where 
            seen? This large jellyfish is sometimes seen on some of our shores. Usually alone, not in groups of many individuals. 
             
            Features: Bell about 10cm in diameter with fat sausage-like oral arms. The arms 
            do not have a long 'tail'.  
             
            Status and threats: There is inadequate information as at 2024 to make an informed assesment of its conservation status in  Singapore.             | 
           
        
       
      
       
      
        
          
            | Fat-armed 
      jellyfishes on Singapore shores | 
           
        
       
      
       
      
        
          
            | Other sightings on Singapore shores | 
           
        
       
       
      
        
           
            Tanah Merah, 
              Dec 10 
              Photo shared by Loh Kok Sheng on his 
                blog. | 
           
            Lazarus Island, Mar 16 
              Photo shared by Jonathan Tan on facebook. | 
            | 
         
       
       
      
       
      
        
          Acknowlegement 
            With grateful thanks to Dr 
              Michael N Dawson of the University of California, Merced for identifying 
            this jellyfish. 
             
            Links
            
              - Checklist of Cnidaria (non-Sclerectinia) Species with their Category of Threat Status for Singapore by Yap Wei Liang Nicholas, Oh Ren Min, Iffah Iesa in G.W.H. Davidson, J.W.M. Gan, D. Huang, W.S. Hwang, S.K.Y. Lum, D.C.J. Yeo, May 2024. The Singapore Red Data Book: Threatened plants and animals of Singapore. 3rd edition. National Parks Board. 663 pp.
 
              - The 
                Scyphozoan website by Dr Michael N Dawson: lots of info about 
                jellyfishes in Class Scyphozoa. 
 
               
              | 
         
       
       | 
      |