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The hatchet fish: surface´s watcher

There are some fish that resemble other animals, such as the crocodile fish or the rooster fish, but there are also other fish that resemble certain objects, such as the sawfish and the protagonist of this article: the hatchet fish. It has an enlarged belly in such a way that it creates an axe. There are many people who have acquired it for their aquariums and it is becoming fashionable.

In this article we will teach you everything about the hatchet fish.

Freshwater hatchet fishes belong to the Gasteropelecidae family. These are fish from South and Central America. For people fond of fish, this species is perfect. It has a deep body that is shaped like an axe. It is usually a small fish that will have a length of about 6.5 cm at most and usually lives between 2 and 5 years of age.

They are quite active fish if they are in a school of at least 8 or more fish. It is a rather curious and moved species, which is why it is gaining fame among fish keepers. They are white with a silver look. They have a horizontal line of black color and that crosses the entire body. The mouth is located on the top of the head, so they have the ability to feed on the surface.

It is a species that is often confused with other hatchet fish of other varieties. The common hatchet fish is somewhat difficult to care for, but it becomes quite a challenge for the most experienced.

Its natural habitat is in South America in Brazil and in the areas where the southernmost tributaries of the Amazon are found. They usually inhabit areas with smaller streams but with a high density of vegetation.

Abundant vegetation is its favorite since it can hide among it and feel protected. He spends most of his time on it. They will only leave the most abundant area when they feel threatened or to feed. They can sometimes be seen coming out of the water to catch flying insects.

a group of fish in surface


They are carnivorous animals. Its mouth is located on the upper part of its body and is used to feed on the surface. They do not usually eat food that has already fallen to the bottom of the stream, as they consider it to be in poor condition. They usually feed on those fed that fall on the surface or on other species of fish that swim at or near the surface.

The food that he pursues is that which is above them, never lowering the level to capture any prey. When he is in the wild, he can catch some vinegar flies, mosquito larvae and almost any food that is on the surface of the water.

If we want to keep it in an aquarium, we must bear in mind that it will only eat the food that is superior to it and that it will not survive only on flake food.

You have to provide a balanced diet based on all kinds of food. For example, bloodworms and fruit flies, as well as some live bloodworms or brine shrimp, can serve as a good source of healthy protein. Of course, it is not necessary to feed it with it daily.

The diet must be varied not only in nutrients, but also in live and dead food. Don’t just fall into the mistake of giving it scales.


If we are going to have it in community aquariums with other species of fish, we must bear in mind that it will be a relatively shy and nervous fish. This is the reason why they have to be placed with other passive fish like them. Some variety of fish that is more aggressive is not recommended. In the extreme case of having to make them live together, we must put a school of at least 8 or more hatchet fish.

If we place it in a school they will adapt more quickly to life in captivity. In addition, as we have mentioned before, they will become more active fish, having a longer life as a consequence. The best fish to accompany them are tetras, corydoras and loricariids.

It is a nocturnal fish that likes to jump out of the water. There are times when it can be seen motionless under the surface of the aquarium water. This is an adaptation that comes from its natural habitat where it is placed there to be able to jump and “fly” through the air in order to catch some flying insects.

Necessary care

They are becoming a really famous species in the world of aquariums since their care is relatively easy. They are animals that, once acclimatized, will always remain healthy. The water must be kept clean and the aquarium system must be closed. Regardless of the size of the aquarium, it should be maintained and cleaned often. The most normal thing is that the organic matter present in the aquarium decomposes and begins to contaminate the environment.

In this type of situation it is somewhat more sensitive. You also have to take into account the hardness of the water. The water must be changed regularly to maintain good conditions. At least 25-50% of the aquarium water should be replaced every two weeks. Thus, the acclimatization process is more positive.

They are fairly disease resistant fish as long as the aquarium is between 15 and 20 gallons in size, even so against bacterial diseases or preventively in their adaptation you can use amoxicillin for fish or ampicillin for fish. If you decorate the aquarium with floating plants and numerous aquarium plants they will be grateful. This is because in their natural habitat they have those conditions and they just need to recreate them.

It is recommended that the tank is tightly closed so that the fish does not fall out if it jumps on instinct. Water conditions must be mild and acidic for them to thrive. A peat filtration is recommended. As for the substrate and the lighting, it can be normal to moderate. The temperature should be between 22 and 27 degrees with a pH between 6 and 7.5.