Hatchetfish, also known as argyropelecus gigas, are brightly colored species of deep-sea fish. These fish are typically reddish or orange. They are usually between two and two and a half inches long and live between 700 and as deep as 3,000 ft. These fish have gotten their name from their hatchet-shaped heads which are heavily spun. These spines are actually extensions of the skull bones. These fish also have a very large mouth and a large oblique mouth.
They are one of the most unique species of fish to ever be discovered. This fish has a very unique way of surviving. They live deep down in the ocean and have adapted to go without a swim bladder. This is a very interesting adaptation to the environment and there is a lot of information to learn about the different parts of their body.
Hatchetfish are a type of deep-sea fish that are found in tropical seas around the world. They are found at different depths and in a wide range of habitats, including coral reefs. These fish are the only known fish that can survive the drop from the surface to the deep-sea pressure.
Their body is specially adapted to cope with the extreme changes in pressure and temperature. Hatchetfishes can be found in the deep waters around Japan, the Philippines, Australia, and the Atlantic coast of South America. There is also a population found in the Mediterranean Sea.
Origin and distribution
It is believed that there are three species of this genus, commonly known as hatchetfish; Carnegiella myersi, Carnegiella marthae, and Carnegiella strigata. Carnegiella strigata is the only species commonly found today in aquarium stores and is represented by no fewer than five subspecies.
Throughout the Guianas in northern South America, hatchetfish are found in marshes, flooded regions, creeks, ditches, as well as in small and large rivers. Throughout the Amazon River basin, this species is especially abundant in the jungle streams.
The hatchetfish hide in marshes and water plants, and on elevated roots just beneath the surface of the water. The insect larvae and small aquatic invertebrates they are looking for constantly draw the shoals together. Instantly, hatchetfish will dash away from danger when a larger fish approaches to prey on them.
Hatchetfish Species profile
In the genus Carnegiella, there are three hatchetfish species: Carnegieella marthae, Carnegiella myersi, and Carnegiella strigata. Among the Carnegiella species, Carnegiella strigata is the most widely recognized, and there are at least five subspecies, all of which can be purchased in aquarium stores today.
There are several places to find hatchetfish in the Guianas, including brooks, flooded areas, ditches, marshes, and small and large rivers. The species is most frequently found in the lower jungle streams of the Amazon River basin.
Hatchetfish prefers to hide beneath the water’s surface, in marshy or stagnant areas, and among elevated roots. Their main food sources are aquatic invertebrates and insect larvae, which they hunt for while shoaling together.
Hatchetfish are named for their unusual shape. They look like a triangle with a flat bottom, similar to the shape of a hatchet from the side. A thin, wedge-shaped knife-edge decorates about a third of the belly, where they taper to a thinner, cracker-like front. Flapping of the fins is made possible by large muscles in the fish’s unusually deep body.
Unlike other hatchetfish, the marbled hatchetfish has a very unique coloration that combines shades of brown, gold, and silvery yellow; the back is green in color with small speckles. Across the flanks are dots that are pink to brown and blend into pale blue.
Two dark stripes are seen along the sides of the head; a darker line extends from the gill covers to the caudal fin and is surrounded on its top by a shiny silvery stripe.
Along the belly border, there are three thin irregular dark blue to brownish-black lines that bend forward and backward. Blackish stripes also appear above the anal fin. The fins appear translucent and pale green. Caudal fins are clearly visible.
The scientific name of the hatchetfish is Argyropelecus gigas
Hatchetfish lives in most temperate waters around the world where they are found hiding at depths that range from 600 ft (180 meters) to around 4,500 ft (1,371 meters)
The average size of the hatchetfish is 2½ inches with the smallest being around 1 inch, while the biggest, as in the case of Thoracocharax securis, is around 3½ inches.
Hatchetfish tank size
The minimum tank size required to keep one hatchetfish is 30 gallons.
Hatchetfish are shoaling fish, meaning they like to be maintained in groups of ten or more. Any battles in the group are only for fun, and no harm is ever done. They are quite accommodating of bottom dwellers and maybe kept safely with other fish of the same size who are quiet and mild-mannered.
Spawning is possible in this species, although it is uncommon. This is an extremely tough fish to breed, and it should only be tried by a professional breeder or someone who enjoys a task and also has the necessary time, space, and patience.
At natural nightfall, this species distributes their eggs amongst thick roots of plants quite close to the surface of the water. Spawning can also occur in the presence of artificial moonlight. Temperature is critical for spawning; 86 degrees F in the late spring or early summer in their native environment.
Males perform a fluttering motion parallel to the females on the branches of beautifully winged plants beneath the water’s surface while spawning.
These fine-leaved plants abore the sticky dispersed eggs. It is not difficult to raise young fry, that hatch around 24 to 30 hours. Feed them rotifers (infusoria) and newborn brine shrimp later on.
Hatchetfish do not eat eggs, thus timing is not as crucial as it is for many other tropical fish. Hatchetfish parents, on the other hand, will aggressively consume the fry as soon as they hatch, therefore the parents should be removed within 24 hours. Also, be certain that the plants that are used in a breeding tank are snail-free, as fish eggs are snail’s preferred diet.
Are they aggressive or peaceful?
It depends on the type of hatchetfish you have. The common hatchetfish, like Blackwing Hatchetfish, can live perfectly with other tropical species in a community tank while the marble hatchetfish are more docile and very territorial.
What they eat
As a carnivore, they eat mosquito larvae, small planktons, crustaceans, small insects above the water level, shrimps, copepods, fish larvae, and tiny worms (e.g. flatworms).
They live in tropical climate streams and prefer water with a pH of 6 to 7, a temperature range of 23 to 27°C (73 to 81°F), and water hardiness of up to 15.0 dGH.
In captivity, they generally live for around 5 years, although they can live longer in the wild.
Parasites and diseases
The most common disease of the hatchetfish is white spot disease caused by a parasite called ich (Ichthyopthirius multifiliis) which is triggered by a sudden drop in aquarium water temperature. Ich can be avoided by maintaining an appropriate water temperature of around 76°F to 80°F for most tropical fish. Carbon and order chemicals should also be removed from the filter.
Aquarium salt or uniodized salt can also be used to treat ich, which lowers the ammonia and nitrite toxicity inside the aquarium. Care should be taken when using salt to treat ich, as some freshwater species of fish are sensitive to salt.
Lateral line diseases, nematode worms, anchorworm, fish lice, and oodinium can all affect your fish and should be treated accordingly.
Do they make good pets?
Yes. Most hatchetfish are hardy and recommended for experienced aquarists.