Tripod Fish: Denizens of the Deep Sea

by Harry F. Sanders, III on January 8, 2019
Featured in Aquatic Animals
Also available in Español

One of the least–well-understood ecosystems in the world is the deep-sea floor. This is understandable. The deep sea can only be reached using robotic submersibles and larger submarine vehicles. This difficulty in reaching the habitat has been a significant barrier to the study of the deep-sea fauna. However, even with these barriers, some creatures have still been studied. One such creature is the remarkably specialized tripod fish. The tripod fish is a truly unique creature that exhibits remarkable evidence of God’s hand in his creation.

Tripod fish are denizens of the deep sea, living up to 6,000 meters below the surface.1 They have a near-worldwide distribution and are uniquely designed for their lifestyle.2 Instead of swimming along the bottom looking for food, this fish lets its food come to it. However, unlike frogfish or similar fish that rely on camouflage and ambush to nab their unsuspecting meal as it comes swimming by, tripod fish do not need to move to hunt.3 Instead, they perch, motionless, on long, spindly fin extensions above the sea floor and pick their prey out of the water column as it floats by.4 Tripod fish acquired their name because they look like they are perched on a tripod above the seafloor.

Tripod fish acquired their name because they look like they are perched on a tripod above the seafloor.

Getting on a Tripod

Despite their habitat, tripod fish are fairly well studied. They are found on “fine sediment” at depth, generally deeper than most light can penetrate.5 They have specialized structures extending from their dorsal or lower fins and caudal or tail fins called rays. These rays are longer than the fish itself and dangle off the fin when the fish swims.6 The rays are highly specialized. They even have “pads at the end of each elongated element that protect the rays while in contact with the sea floor.”7 Think of it this way: when someone spends a long time working on their knees, they wear kneepads to ease the stress on their joints. The stress is caused by the weight of the body resting upon the knees. When the tripod fish puts down its tripod, all the weight of the fish rests on the rays. Without these pads, the ends of the rays would blister, fester, and potentially become infected.

Tripod fish’s ability to land on the seafloor after swimming is also remarkable. When they decide to touch down, they will cease swimming and allow themselves to slowly sink to the seafloor, with their front two “legs” of the tripod extended downwards. The tail “leg” of the tripod however points directly rearward, possibly serving as a balance point for the fish as it sinks. Once the front two touch the ocean floor, the tripod fish brings the third “leg” down to the seafloor and resumes its typical tripod stance.8

However, this is not the only feature which makes tripod fish well adapted to life on the seafloor. They have a very small swim bladder.9 This is important because of the pressure of the deep sea. If they had a standard swim bladder of a shallow water fish, it would have a significant problem. The swim bladder is a gas filled organ that helps fish maintain a neutral buoyancy so it does not sink or rise in the water column uncontrollably.10 Because of the increased pressure from the water above, the gas inside is compressed. If the tripod fish had a normal swim bladder, it would be crushed at its depth, killing the fish, or crippling it. Because it is small, the gas compression is not as severe and it is not crushed, even at the 6,000-meter maximum depth of the fish.

Tripod Feeding

Tripod fish have other features that make them fit to survive on the seabed. They are able to detect current and face into it. This allows their preferred prey, zooplankton, to be funneled into their mouth without them having to make the slightest effort to catch them.11 Due to specialized gills resembling those found in filter feeders, the tripod fish has been assumed to filter feed also, but there has been no confirmation of this yet.12 However, if a particular morsel seems attractive, it is believed that tripod fish have a mechanism to track it. Despite the near complete darkness in which they live, tripod fish have highly specialized vision.13 Their retinas are pointed front and back. “This retinal design is well suited to the tripod fish, a sit-and-wait predator that feeds on small bioluminescent copepods that wash by in the current. The temporal (frontally directed) areae retinae might be used to detect a copepod that suddenly appears in the frontal ventral visual field, the part of the visual field where prey is expected to arrive.”14 In other words, the eyes of the tripod fish are designed to do exactly what they do. Tripod fish also are believed to use their pectoral fins as sensors to detect the movement of prey in the dark, due to enlarged nerves in the area.15 It appears tripod fish were designed to straddle the seafloor and exist in the same manner that they do today.

It appears tripod fish were designed to straddle the seafloor and exist in the same manner that they do today.

Tripod fish have several other remarkable features. They have a pineal gland as most vertebrates do, but theirs is smaller than most other fish.16 This makes sense in light of the pineal gland’s role in producing melatonin to regulate the sleep cycle of vertebrates. The pineal gland is triggered by changes of light and darkness.17 Since the deep sea is dark all the time, a normal pineal gland would produce too much melatonin, leading to the tripod fish resting far more than it needed to rest. The smaller pineal gland points strongly to forethought and design.

Tripod by Design

With all these remarkable features, tripod fish are challenging to evolutionists. They give every appearance of having been designed to live on the seafloor. However, design is an anathema to evolutionists. Sir Francis Crick, codiscoverer of the structure of DNA, wrote, “Biologists must constantly keep in mind that what they see was not designed, but rather evolved.”18 Richard Dawkins went a step further in his book The Blind Watchmaker. He wrote, “Natural selection, the blind, unconscious, automatic process which Darwin discovered, and which we now know is the explanation for the existence and apparently purposeful form of all life, has no purpose in mind. It has no mind and no mind’s eye. It does not plan for the future. It has no vision, no foresight, no sight at all.”19 However, this distinct lack of purpose is the direct opposite of what we observe from the tripod fish.

With all these remarkable features, tripod fish are challenging to evolutionists. They give every appearance of having been designed to live on the seafloor.

In order to function correctly in their environment, the tripod fish requires numerous features, without which it would either die or be less able to survive in its environment. Due to its depth, its swim bladder must be smaller than the average fish to keep it from being crushed as it descends. It requires a smaller pineal gland to ensure it is able to maintain the correct balance of rest and activity. In order to feed, it needs to be able to sense the direction of the current so it can face into it. However, since current is essentially non-existent along the bottom of the ocean, to feed from the current, the tripod fish has to be in a location where there is current. Conveniently, it has a lengthy tripod that elevates it off the seabed so it can feed from the current. Yet Dawkins says evolution has no forethought. All these features, and more, needed to be in place simultaneously for the tripod fish to survive.

This places evolutionary dogma in a very difficult position. The tripod fish clearly points to the Creator, but, as Crick said, they must believe it somehow evolved. Perhaps because it is somewhat obscure and perhaps because there is no answer, how tripod fish evolved is a question that they have not even attempted to address. A focused search of google scholar for “evolution tripod fish” yields zero results. This is also true if the genus name is substituted for the common name “tripod fish.”20 One author in a lay science magazine speculated that the tripod fish evolved its stilts in order to be taller21; however, this is directly opposed to Dawkins' dictum that evolution has no purpose in mind.22

For the creationist, the tripod fish is a marvelous example of God’s handiwork in his creation. It also is an excellent example of the detail he built into his world. He knew it would take thousands of years after he made the fish in Genesis 1:20–21 for man to reach the ocean floor and discover creatures like the tripod fish. Despite this, he created them anyway, to bring glory to himself and for man to, eventually, learn from and enjoy.


  1. Arturo Angulo, William A. Bussing, and Myrna I. Lopez, “Occurrence of the Tripodfish Bathypterois ventralis (Aulopiformes: Ipnopidae) in the Pacific Coast of Costa Rica,” Revista Mexicana de Biodiversidad 86, no. 2 (June 2015): 546–549, doi:10.1016/j.rmb.2015.04.025.
  2. Ibid.
  3. Casey Patton, “Longlure Frogfish,” Florida Museum, accessed October 18, 2018,
  4. Jansen Zuanon, Flávio A. Bockmann, and Ivan Sazima, “A Remarkable Sand-Dwelling Fish Assemblage from Central Amazonia, with Comments on the Evolution of Psammophily in South American Freshwater Fishes,” Neotropical Ichthyology 4, no. 1 (January–March 2006): 107–118, doi:10.1590/S1679-62252006000100012.
  5. E. H. Chave and Anthony T. Jones, “Deep-Water Megafauna of the Kohala and Haleakala Slopes, Alenuihaha Channel, Hawaii,” Deep-Sea Research Part A. Oceanographic Research Papers 38, no. 7 (July 1991): 781–803, doi:10.1016/0198-0149(91)90019-C
  6. Anthony T. Jones and Kenneth J. Sulak, “First Central Pacific Plate and the Hawaiian Record of the Deep-sea Tripod Fish Bathypterois grallator (Pisces: Chlorophthalmidae),” Pacific Science 44, no. 3 (1990): 254–257,
  7. Matthew P. Davis and Prosanta Chakrabarty, “Tripodfish (Aulopiformes: Bathypterois) Locomotion and Landing Behavior from Video Observation at Bathypelagic Depths in the Campos Basin in Brazil,” Marine Biology Research 7 (2011): 297–303,
  8. Ibid. A video of this behavior is available at The video will start to download once you select the link. It is a very interesting video and demonstrates this remarkable behavior well.
  9. Edgar Cruz-Acevedo, Miguel Betancourt-Lozano, and Hugo Aguirre-Villaseñor, “Distribution of the Deep-Sea Genus Bathypterois (Pisces:Ipnopidae) in the Eastern Central Pacific,” Revista de Bilogia Tropical 65, no. 1 (2017): doi:10.15517/rbt.v65i1.23726.
  10. Adrienne Calo, “Science Spotlight: Fish, Swim Bladders and Boyle’s Law,” Quest, March 12, 2015, accessed October 18, 2018,
  11. John C. Montgomery and John A. Macdonald, “Evolution of Sensory Systems: A Comparison of Antarctic and Deep-Sea Ichthyofauna,” in Fishes of Antarctica, ed. Guido Di Prisco, Eva Pisano, and Andrew Clark (Milano, ItaliY: Springer, 1998): 329–338, doi:10.1007/978-88-470-2157-0_28.
  12. Davis and Chakrabarty, “Tripodfish.”
  13. S. P. Collin and J. C. Partridge, “Fish Vision: Retinal Specialization in the Eyes of Deep-Sea Teleosts,” Journal of Fish Biology 49, Supplement A (1996): 157–174,
  14. Eric J. Warrant, Shaun P. Collin, and N. Adam Locket, “Eye Design and Vision in Deep-Sea Fishes,” in Sensory Processing in Aquatic Environments, eds. Shaun P. Collin and N. Justin Marshall (New York: Springer, 2003), 303–322, doi:10.1007/978-0-387-22628-6_16.
  15. Ken Sulak, “The Systematics and Biology of Bathypterois (Pisces, Chlorophtalmidae) with a Revised Classification of Benthic Myctophiform Fishes,” Galathea Rep. 14 (1977): 49–108,
  16. H.-J. Wagner and U. Mattheus, “Pineal Organs in Deep Demersal Fish,” Cell and Tissue Research 107, no. 1 (2002): 115–127, doi:10.1007/s00441-001-0482-y.
  17. Charles Emerson, “Pineal Gland,” Encyclopedia Britannica, last updated September 4, 2015, accessed October 18, 2018,
  18. Francis Crick, What Mad Pursuit: A Personal View of Scientific Discovery (New York: Basic Books, 1988).
  19. Richard Dawkins, The Blind Watchmaker (New York: W. W. Norton & Company, Inc., 1996).
  20. Searches performed October 19, 2018.
  21. Bec Crew, “Tripod Fish: A Deep-Sea Fish Able to ‘Stand’,” Australian Geographic, March 20, 2014, accessed October 19, 2018,
  22. Dawkins, The Blind Watchmaker.


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