Phylum

Common name: Cnidarians

Scientific name: Cnidaria

Cnidaria is a diverse phylum of aquatic animals renowned for their distinctive radial symmetry and specialized cells known as cnidocytes, which contain stinging organelles called nematocysts. This phylum includes a wide array of species such as jellyfish, corals, sea anemones, and hydras. Cnidarians are primarily marine organisms, although some can be found in freshwater environments. They exhibit two main body forms: the sessile polyp and the free-swimming medusa, with some species capable of alternating between these forms during their life cycle.

One of the most fascinating aspects of Cnidaria is their role in reef ecosystems. Corals, which are colonial cnidarians, are the primary architects of coral reefs. They form symbiotic relationships with zooxanthellae, photosynthetic algae that live within their tissues. This symbiosis is crucial for the health of coral reefs, as the algae provide nutrients to the corals through photosynthesis, while the corals offer the algae a protected environment and access to sunlight.

For hobbyists, Cnidaria offers a variety of species that can be kept in home aquariums, ranging from the colorful and relatively easy-to-care-for soft corals to the more demanding stony corals. When keeping cnidarians, it is important to consider their lighting, water flow, and water quality needs, as these factors are critical to their survival and growth. Additionally, many cnidarians have potent stinging cells that can harm other tank inhabitants or even the aquarist, so careful handling and placement within the aquarium are necessary.

Overall, Cnidaria is a captivating phylum that not only plays a vital role in marine ecosystems but also offers intriguing and beautiful species for aquarium enthusiasts. Their unique biological features and ecological importance make them a subject of interest for both hobbyists and scientists alike.

  1. Macro photography of Acanthastrea echinata coral in reef aquarium
    Common name: Starry Cup Coral
    Scientific name: Acanthastrea echinata
  2. Common name: Acan Coral
    Scientific name: Acanthastrea hemprichii
  3. Common name: Abrolhos Acropora
    Scientific name: Acropora abrolhosensis
  4. Common name: Aculeus Staghorn Coral
    Scientific name: Acropora aculeus
  5. Common name: Acropora azurea
    Scientific name: Acropora azurea
  6. Common name: Acropora batunai
    Scientific name: Acropora batunai
  7. Common name: Acropora bifurcata
    Scientific name: Acropora bifurcata
  8. Bushy Acropora SPS Coral in saltwater reef aquarium tank
    Common name: Bushy Acropora
    Scientific name: Acropora bushyensis
  9. Caribbean coral garden staghorn coral
    Common name: Staghorn Coral
    Scientific name: Acropora carduus
  10. Caribbean coral garden staghorn coral
    Common name: Staghorn Coral
    Scientific name: Acropora caroliniana
  11. Common name: Corymbose branching plate coral
    Scientific name: Acropora cerealis
  12. Common name: Chesterfield Staghorn Coral
    Scientific name: Acropora chesterfieldensis
  13. Acropora digitifera EG-082
    Common name: Digitate Acropora
    Scientific name: Acropora digitifera
  14. Table coral, Acropora Divaricat in Thailand
    Common name: Staghorn Coral
    Scientific name: Acropora divaricata
  15. Apropora echinata frag small polyp stony coral in aquarium
    Common name: Blueberry Sea Fan
    Scientific name: Acropora echinata
  16. Egg-sperm bundles before spawning of Acropora elseyi
    Common name: Acropora elseyi
    Scientific name: Acropora elseyi
  17. Critically Endangered Staghorn Coral
    Common name: Stout irregular branching coral
    Scientific name: Acropora florida
  18. Acropora Formosa and a Scissortail Sergeant - Abudefduf Sexfasciatus
    Common name: Formosa Staghorn Coral
    Scientific name: Acropora formosa
  19. Common name: Acropora forskali
    Scientific name: Acropora forskali
  20. Polyp stony coral Acropora gemmifera undersea, Red Sea, Egypt, Sharm El Sheikh, Nabq Bay
    Common name: Branching Acropora
    Scientific name: Acropora gemmifera
  21. Common name: Staghorn Coral
    Scientific name: Acropora grandis
  22. Common name: Granulosa Acropora
    Scientific name: Acropora granulosa
  23. Blue Acropora hemprichii coral in Red Sea
    Common name: Hemprich's Acropora
    Scientific name: Acropora hemprichii
  24. Common name: Acropora horrida
    Scientific name: Acropora horrida
  25. Polyp stony coral finger coral (Acropora humilis) undersea, Red Sea, Egypt, Sharm El Sheikh, Nabq Bay
    Common name: Finger coral
    Scientific name: Acropora humilis
  26. Common name: Acropora jacquelineae
    Scientific name: Acropora jacquelineae
  27. Common name: Acropora kimbeensis
    Scientific name: Acropora kimbeensis
  28. Acroporid coral Acropora lamarcki undersea, Red Sea, Egypt, Sharm El Sheikh, Nabq Bay
    Common name: Lamarck's Staghorn Coral
    Scientific name: Acropora lamarcki
  29. Baby Lyretail Hogfish in Table Coral
    Common name: Acropora latistella
    Scientific name: Acropora latistella
  30. Common name: bluetip coral
    Scientific name: Acropora loripes
  31. Common name: Acropora lovelli
    Scientific name: Acropora lovelli
  32. Common name: Acropora maryae
    Scientific name: Acropora maryae
  33. coral reef
    Common name: Acropora microphthalma
    Scientific name: Acropora microphthalma
  34. Acropora millepora colorful sps coral on black background
    Common name: Fluro scale cushion coral
    Scientific name: Acropora millepora
  35. leaf plate montipora
    Common name: Montipora Capricornis
    Scientific name: Acropora monticulosa
  36. Common name: Acropora multiacuta
    Scientific name: Acropora multiacuta
  37. Common name: Acropora nana
    Scientific name: Acropora nana
  38. Stone Coral Acropora nasuta.
    Common name: Acropora nasuta
    Scientific name: Acropora nasuta
  39. Acropora coral under the sea
    Common name: Acropora nobilis
    Scientific name: Acropora nobilis
  40. Isopora palifera
    Common name: Column Staghorn Coral
    Scientific name: Acropora palifera
  41. Schooling fish surround Elkhorn coral (Acropora palmata, Florida Keys
    Common name: elkhorn coral
    Scientific name: Acropora palmata
  42. Common name: Acropora parilis
    Scientific name: Acropora parilis
  43. Baby Lyretail Hogfish in Table Coral
    Common name: Pharaoh's Acropora
    Scientific name: Acropora pharaonis
  44. Common name: fused staghorn
    Scientific name: Acropora prolifera
  45. Tropical fish double-saddle butterflyfish over staghorn coral, underwater in the lagoon, Pacific ocean, Huahine, French Polynesia
    Common name: Acropora pulchra
    Scientific name: Acropora pulchra
  46. Lionfish hiding in Robust staghorn coral reef in Andaman sea
    Common name: Acropora robusta
    Scientific name: Acropora robusta
  47. Common name: Acropora sarmentosa
    Scientific name: Acropora sarmentosa
  48. Common name: Acropora schmitti
    Scientific name: Acropora schmitti
  49. Common name: Acropora secale
    Scientific name: Acropora secale
  50. Common name: Acropora selago
    Scientific name: Acropora selago
  51. Common name: Acropora seriata
    Scientific name: Acropora seriata
  52. Caribbean coral garden staghorn coral
    Common name: Staghorn Coral
    Scientific name: Acropora spicifera
  53. Polyp stony coral Acropora squarrosa undersea, Red Sea, Egypt, Sharm El Sheikh, Nabq Bay
    Common name: Acropora squarrosa
    Scientific name: Acropora squarrosa
  54. Polyp stony coral Acropora subulata undersea, Red Sea, Egypt, Sharm El Sheikh, Nabq Bay
    Common name: Acropora subulata
    Scientific name: Acropora subulata
  55. Common name: Acropora suharsonoi
    Scientific name: Acropora suharsonoi
  56. Closeup shot of acropora tenuis corals underwater
    Common name: purple tipped acropora
    Scientific name: Acropora tenuis
  57. Common name: Blue Tort Acropora
    Scientific name: Acropora tortuosa
  58. Common name: Acropora tumida
    Scientific name: Acropora tumida
  59. Common name: Acropora valenciennesi
    Scientific name: Acropora valenciennesi
  60. Bushy Acropora SPS Coral in saltwater reef aquarium tank
    Common name: Acropora valida
    Scientific name: Acropora valida
  61. Common name: Acropora variolosa
    Scientific name: Acropora variolosa
  62. Common name: Acrozoanthus Australiae
    Scientific name: Acrozoanthus australiae
  63. Closeup shot of a beadlet anemone (Actinia equina) underwater
    Common name: Beadlet anemone
    Scientific name: Actinia equina
  64. White-spotted Rose Anemone
    Common name: Strawberry anemone
    Scientific name: Actinia fragacea
  65. Waratah Anemones underwater
    Common name: Waratah anemone
    Scientific name: Actinia tenebrosa
  66. Common name: tree anemone
    Scientific name: Actinodendron arboreum
  67. Blue-ring octopus on red branching coral
    Common name: Branching anemone
    Scientific name: Actinodendron glomeratum
  68. Common name: Branching anemone
    Scientific name: Actinodendron plumosum
  69. Actinostephanus haeckeli - Haeckels Sandanemone
    Common name: Haeckel's Anemone
    Scientific name: Actinostephanus haeckeli
  70. Whitestar Sheet Coral on Caribbean Coral Reef
    Common name: sheet coral
    Scientific name: Agaricia lamarcki
  71. Small glass anemone pest in reef aquarium tank - Exaiptasia or Aiptasia Pallida
    Common name: Trumpet anemone
    Scientific name: Aiptasia mutabilis
  72. Small glass anemone pest in reef aquarium tank - Exaiptasia or Aiptasia Pallida
    Common name: pale anemone
    Scientific name: Aiptasia pallida
  73. A closeup picture of the soft coral dead man's fingers or Alcyonium digitatum. Picture from the Weather Islands, Skagerrak Sea, western Sweden
    Common name: dead man's fingers
    Scientific name: Alcyonium digitatum
  74. Coral reef South Pacific
    Common name: Red sea fingers
    Scientific name: Alcyonium glomeratum
  75. Dead Man's Fingers
    Common name: Dead Man's Fingers
    Scientific name: Alcyonium palmatum
  76. Branching flower pot coral, Porenkoralle (Alveopora catalai)
    Common name: Net coral
    Scientific name: Alveopora catalai
  77. Nahaufnahme von Alveopora gigas im Meerwasseraquarium
    Common name: Alveopora Coral
    Scientific name: Alveopora gigas
  78. Amplexidiscus fenestrafer coral.
    Common name: Giant Cup Mushroom Coral
    Scientific name: Amplexidiscus fenestrafer
  79. Mediterranean false orange coral (Dendrophyllia ramea)
    Common name: False flower coral
    Scientific name: Anacropora forbesi
  80. Common name: Manjano Anemone
    Scientific name: Anemonia manjano
  81. Mediterranean Sea Anemone (Snakelocks Anemone, Anemonia Viridis), Kornati Archipelago, Adriatic Sea, Croatia
    Common name: Snakelocks anemone
    Scientific name: Anemonia viridis
  82. Red Sea coral reef with hard coral  Anomastraea irregularis.
    Common name: Anomastraea irregularis
    Scientific name: Anomastraea irregularis
  83. Waving Hand Coral (Anthelia) colony in the Red Sea
    Common name: Waving Hand Coral
    Scientific name: Anthelia glauca
  84. Anemone Mandala 03
    Common name: giant green anemone
    Scientific name: Anthopleura xanthogrammica
  85. Common name: slimy sea plume
    Scientific name: Antillogorgia americana
  86. Colonial soft coral bipinnate sea plume or forked sea feather (Antillogorgia bipinnata) undersea, Caribbean Sea, Cuba, Playa Cueva de los peces
    Common name: forked sea feather
    Scientific name: Antillogorgia bipinnata
  87. Common name: Sea Plume
    Scientific name: Antillogorgia elisabethae
  88. Common name: Galapagos black coral
    Scientific name: Antipathes galapagensis
  89. A beautiful Colourful soft corals, hard coral, feather star, anemone and marine in Koh Lipe, Thailand
    Common name: Starflower coral
    Scientific name: Astreopora listeri
  90. Moon Jellyfish (Aurelia aurita) in an aquarium
    Common name: Moon Jellyfish
    Scientific name: Aurelia aurita
  91. Green euphyllia lps coral in reef aquarium tank
    Common name: Branching Frogspawn Coral
    Scientific name: Australogyra zelli
  92. Pederson Cleaner Shrimp (Periclimenes pedersoni) in Corkscrew Anomones (Bartholomea annulata)
    Common name: corkscrew anemone
    Scientific name: Bartholomea annulata
  93. Common name: Curlycue Anemone
    Scientific name: Bartholomea lucida
  94. Low light picture of blastomussa merleti  coral in green and purple close up macro - selective focus on one polyp and selective blur
    Common name: Branched cup coral
    Scientific name: Blastomussa merleti
  95. Big Polyp Blastomussa LPS Coral - (Blastomussa wellsi)
    Common name: Branched cup coral
    Scientific name: Blastomussa wellsi
  96. Swimming sea anemone in blue water, Boloceroides mcmurrichi
    Common name: Bulb Anemone
    Scientific name: Boloceroides mcmurrichi
  97. Common name: corky sea fingers
    Scientific name: Briareum asbestinum
  98. A hermit crab (Dardanus pedunculatus) has a symbiotic relationship with anemones (Calliactis polypus) that provide camouflage and protection.
    Common name: Hermit crab anemone
    Scientific name: Calliactis polypus
  99. Common name: Cantharellus jebbi
    Scientific name: Cantharellus jebbi
  100. Tree soft Coral (Capnella Imbricata) in the filipino sea 7.2.2015
    Common name: Kenya Tree Coral
    Scientific name: Capnella imbricata
  101. Cup corals, Runde Nelkenkoralle (Caryophyllia inornata)
    Common name: carnation coral
    Scientific name: Caryophyllia inornata
  102. Carnation coral, Ovale Nelkenkoralle (Caryophyllia smithii)
    Common name: Devonshire cup-coral
    Scientific name: Caryophyllia smithii
  103. Upside-down Jellyfish (Cassiopea andromeda) swimming under surface of water, Red sea, Egypt
    Common name: Upside-down Jellyfish
    Scientific name: Cassiopea andromeda
  104. Mangrove Upside-down Jellyfish
    Common name: Mangrove Upside-down Jellyfish
    Scientific name: Cassiopea xamachana
  105. Blue tip Elegance LPS coral - Catalaphyllia Jardinei
    Common name: Elegance coral
    Scientific name: Catalaphyllia jardinei
  106. Candy cane LPS coral - Caulastrea furcata
    Common name: Candy Cane Coral
    Scientific name: Caulastraea connata
  107. Caulastrea echinulata im Aquarium
    Common name: Finger coral
    Scientific name: Caulastraea echinulata
  108. Candy cane LPS coral - Caulastrea sp.
    Common name: Finger coral
    Scientific name: Caulastraea furcata
  109. Acropora millepora colorful sps coral on black background
    Common name: Finger coral
    Scientific name: Caulastraea tumida
  110. Trumpet Coral (Caulastrea curvata) in aa reef aquarium (LPS coral)
    Common name: Finger coral
    Scientific name: Caulastrea curvata
  111. ウミサボテン
    Common name: Cavernularia obesa
    Scientific name: Cavernularia obesa
  112. Common name: southern cerianthid
    Scientific name: Ceriantheopsis americana
  113. Tube Anemone, Faden-Zylinderrose (Cerianthus filiformis)
    Common name: Large tube anemone
    Scientific name: Cerianthus filiformis
  114. closeup of a brown and white tube dwelling sea anemone, a popular aquarium pet in aquaculture
    Common name: Cylinder Anemone
    Scientific name: Cerianthus lloydii
  115. Cerianthus membranaceus and two scorpion fish
    Common name: Tube Anemone
    Scientific name: Cerianthus membranaceus
  116. A mated pair of gobies (Bryaninops yongei) sits on wire coral (Cirrhipathes anguina) at night on a black background; Indonesia
    Common name: whip Coral
    Scientific name: Cirrhipathes anguina
  117. Common name: Colt Coral
    Scientific name: Cladiella australis
  118. Stony coral rasp coral, or cauliflower coral, knob-horned coral (Pocillopora verrucosa) undersea, Red Sea, Egypt, Sharm El Sheikh, Nabq Bay
    Common name: Cauliflower Coral
    Scientific name: Cladiella pauciflora
  119. Purple tube sponges in the Caribbean Sea
    Common name: tube coral
    Scientific name: Cladocora arbuscula
  120. Giant clam, Tridacna gigas, surrounded by soft corals, Clavularia viridis, Raja Ampat Indonesia.
    Common name: Green Star Polyps
    Scientific name: Clavularia viridis