When we think of other animals, we often refer to species that have a rather similar body plan as us, or in other terms that look like us; while everything deviating from that is easily qualified, and unfairly, as monsters. The order Lophiiformes, commonly called anglerfishes, present possibly some of the most strange-looking fish you have ever seen. 👽 With 320 species currently described worldwide, they occupy various depths in the oceans, ranging from shallow tropical waters, to depths reaching more than 3600 m in the deep sea.
The species introduced here belongs to the family Lophiidae which we commonly call goosefishes 𓅼 or monkfishes 🧘🏼, as fishermen in the past believed that these fishes can swallow a goose whole. There are around 25 species described in this family, living at depths of 200 m to 1000 m deep , but some also occasionally dwell in shallow coastal areas as well. All species of this family are easily recognizable by their disproportionately large head and mouth, as well as their flattened and narrowed bodies that often also have camouflage patterns to hide from predators in the sandy bottoms of the oceans. These fishes, however, are far from being small as they can grow as much as to reach a human-size, up to 1.8 m in length! They are themselves predators – feeding opportunistically on fishes or invertebrates, but when chances allow, seabirds might also be on their menu! Sometimes brought by ocean currents from the bottoms to the sea surface, they definitely wouldn’t miss the opportunity to prey on this feathery meal.🍴
The goosefishes have every part of their body adapted for hunting. The most fascinating one is probably their distinctive “fishing rod” on their heads – known as the illicium. 🎣 This structure is a modification of their first dorsal fin spine into a stalk with a fleshy tip – the esca – acting as a “bait”. This bait-looking growth is used to attract and hunt fishes that might have mistaken it for a sickly small fish. The sophistication of the esca gets another surprising twist in other deep sea anglerfish such as in the Melanocetidae and Himantolophidae families. These species have glow-in-the-dark "fishing rods" – which are actually bioluminescence produced by endosymbiotic bacteria present within their escas! 💡 It is particularly difficult to find food in the deep sea, especially when it's basically pitch-black, so having a light-emitting esca further increases their chances of attracting potential prey.
Goosefishes, however, do not possess bioluminescence but instead use a discreet strategy to capture other fishes. This species adopts a sit-and-wait strategy to hunt, meaning that they blend into the environment and wait for the exact right moment when the prey passes nearby to ambush it. 🤫 This also explains why they have such an unusual body plan – their flattened and camouflaged body allow them to easily remain concealed in sandy bottoms of the ocean; while their large head and mouth equipped with a protractile upper jaw and projecting lower jaw bearing numerous sharp teeth 🦷 increases their chances of a successful ambush. 📈 Even their eyes are facing upwards instead of sideways, just to make sure they won't miss anything passing above them that they could catch for food. 👀
During “fishing”, the goosefish remains stationary on the ocean bottom to conceal itself, while erecting its esca and flicking it back and forth randomly to mimic a smaller fish swimming around. 🐟 This basically sets a trap for curious fish perceiving this smaller “fish” as potential food, making them swim closer to investigate. 🧐 Once close enough, the goosefish is then ready for an ambush – quickly retreating its esca which lays back horizontally - launches upwards and engulfes the prey in a snap by creating a rapid suction pressure thanks to their flexible and expandable oral cavity. This gape-and-suck method 💨 , along with their depressible teeth which prevents prey from breaking free, makes them able to swallow prey double of their size. Within a split second, the unlucky fish would disappear in the goosefish’s mouth, having then no chance to escape. ☠️
If you are interested in seeing the remarkable features of goosefish and other astonishing species, don’t hesitate to book a session and come visit us!
Text: Rachel Au
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