Marbled Hatchetfish

River Hatchetfish

Family: Gasteropelecidae Marbled Hatchetfish, Carnegiella strigata, River HatchetfishCarnegiella strigataPhoto Wiki Commons, Courtesy LA Dawson.
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Marble hatchet fish caught my eye in a tropical fish store as one of the most serene fish i have ever seen before. I decided to purchase 5 of them and placed them... (more)  Tony

The Marbled Hatchetfish is a very unique looking fish with its unusual 'hatchet' shaped body and pretty patterning!

The Marble Hatchetfish Carnegiella strigata is a River Hatchetfish. Its common and scientific names are both very descriptive in recognizing this species, as well as a bit informative. At the family level, the term Gasteropelecidae means "hatchet-shaped belly", which is readily apparent in its appearance. The genus is named after Margaret Carnegie, as seen in the term Carnegiella, and its species name strigatas means "streaked".

The hatchetfishes of the family Gasteropelecidae leap from the water and fly through the air, flapping their large pectoral fins to catch flying insects.. They are generally accepted as being the only true "flyingfish" as they are the only fish that move their pectoral fins to aid in their flight!

Though quite original looking, it is very similar in shape to other freshwater hatchetfish, including its close cousin the Common Hatchetfish Gasteropelecus sternicla. Its differences are in a distinctive marbled coloring and being smaller.

The Marbled Hatchetfish are a peaceful community fish, but not quite as hardy as the Common Hatchetfish. They will eat a flake food, but cannot survive on it alone. They must be fed proteins such as mosquito larvae and bloodworms. Because they are prone to ich, it is recommended that they be kept in a quarantine tank for a couple of weeks before introducing them to a community aquarium.

Marbled Hatchetfish are also a schooling fish and should be kept in groups of 6 or more. They are a shy nervous little fish, and need the companionship of their own kind to be comfortable and settle in. They like to hang at the surface of the water and they like to jump, so keep a good top on the aquarium. These fish will appreciate some floating plants, but with their mouth situated up on top of their body you can see that the Marbled Hatchetfish must be used to eating at the surface. Be sure to provide some clear areas on the surface for them to feed.

For Information on keeping freshwater fish, see:
Freshwater Aquarium Guide: Aquarium Setup and Care

Geographic Distribution
Carnegiella strigata
Data provided by
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Characiformes
  • Family: Gasteropelecidae
  • Genus: Carnegiella
  • Species: strigata
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Marbled Hatchetfish - Quick Aquarium Care
  • Aquarist Experience Level: Intermediate
  • Size of fish - inches: 2.0 inches (5.00 cm)
  • Minimum Tank Size: 15 gal (57 L)
  • Temperament: Peaceful
  • Aquarium Hardiness: Moderately hardy
  • Temperature: 75.0 to 82.0° F (23.9 to 27.8° C)
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Habitat: Distribution / Background

The Marble Hatchetfish Carnegiella strigata was described by Günther in 1864. This species is not listed on the IUCN Red List. They are found in South America in the countries of Colombia, Guyana, Suriname, Peru and Brazil. They are also known as River Hatchetfish.

They occur throughout the Amazon River basin, lower, middle and upper, as well as the Caqueta River in Colombia. These freshwater hatchetfish inhabit forest streams and tributaries, generally in areas with a lot of surface vegetation. They live in groups and spend almost all of their time at the water surface feeding on crustaceans and insects.

The Marbled Hatchetfish species Carnegiella strigata strigata are found in Iquitos, Peru. A similar hatchetfish, the Carnegiella strigata fasciata are found in Guyana. The fish from Guyana are supposed to be easier to keep but it is difficult to tell the difference between the species.

  • Scientific Name: Carnegiella strigata
  • Social Grouping: Groups
  • IUCN Red List: NE - Not Evaluated or not listed


The Marbled Hatchetfish is a small deep bodied fish with a 'hatchet' type shape to it. This fish will generally reach about 2 inches (5 cm) in length and has a life span of about 2 - 5 years. They will be more active and have the longer life span if kept in a good sized group, ideally with six or more fish. They are basically a white color with a black marble pattern which looks like black and white stripes running diagonally across them. They have a mouth situated close to the top of their head for feeding at the surface.

  • Size of fish - inches: 2.0 inches (5.00 cm) - In the wild these fish only reach about 1 1/2 inches (4 cm), but aquarium specimens grow larger, reaching up to about 2 inches (5 cm).
  • Lifespan: 5 years - They have a life span of about 2 - 5 years. They will have a longer lifespan and be more active if kept in a group, ideally of 6 or more fish.

Fish Keeping Difficulty

The Marbled Hatchetfish is moderately hardy, best suited for an aquarist with some fish keeping experience. These fish often have trouble surviving in aquariums as the are very shy feeders and will not normally take dried foods. They also are very susceptible to Ich, particularly newly imported species. It is suggested that new purchases be acclimated in a quarantine tank for two or three weeks before introducing them into a community aquarium.

  • Aquarium Hardiness: Moderately hardy - This fish is highly susceptible to ich particularly when introduced to a new a aquarium. It is suggested that new purchases be kept in a quarantine tank.
  • Aquarist Experience Level: Intermediate

Foods and Feeding

These freshwater hatchetfish are carnivores. With their mouth situated up on top of their body you can see they must be used to eating surface. These fish will normally not eat anything the falls below them as the are strictly surface feeders and can only see what is above them. In the wild they will eat foods such as small vinegar flies and mosquito larvae.

In the aquarium the Marbled Hatchetfish will generally eat all kinds of foods as long as it is on the surface of the water, however they will not survive with just a flake food. To keep a good balance give them a protein such as Black mosquito larvae, fruit flies, blood worms, or brine shrimp (either live or frozen) everyday. It's important to make sure the foods that are fed to these fish stay at the surface longer then most.

  • Diet Type: Omnivore - Their diet should must supplemented with live foods, flake foods are not enough.
  • Flake Food: Yes
  • Tablet / Pellet: Yes
  • Live foods (fishes, shrimps, worms): Some of Diet
  • Vegetable Food: Some of Diet
  • Meaty Food: Some of Diet
  • Feeding Frequency: Several feedings per day

Aquarium Care

Marbled Hatchetfish are not exceptionally difficult to care for once they are acclimated, provided their water is kept clean. Aquariums are closed systems and regardless on size all need some maintenance. Over time decomposing organic matter, nitrates, and phosphate build up and the water hardness increases due to evaporation. To combat these ever changing conditions water should be replaced on a regular basis, especially if the tank is densely stocked. At least 25 - 50% of the tank water should be replaced every other week.

  • Water Changes: Bi-weekly

Aquarium Setup

These fish are moderately hardy once they are established. A school of 6 or more Marbled Hatchetfish will need about a 15 to 20 gallon aquarium as a minimum. They will mostly swim and feed at the surface of the water. They will appreciate some floating plants, but as they eat at the surface some clear areas need to be provided as well. There should be a moderate current in the tank, this can be accomplished using a strong canister filter or powerheads. The tank should be tightly sealed as this fish is apt to jump out of the tank if provided the opportunity.

These freshwater hatchetfish are prone to ich, especially when first introduced to a new aquarium. It is suggested they be acclimated in a quarantine aquarium for two to three weeks before being placed in their permanent home. This blackwater native is very intolerant of harder and more alkaline water. The water conditions should be kept soft and acidic for them to thrive. Peat filtration is advisable. This fish enjoys a sandy substrate with a few handfuls of leaves added.

  • Minimum Tank Size: 15 gal (57 L)
  • Suitable for Nano Tank: Yes
  • Substrate Type: Any
  • Lighting Needs: Moderate - normal lighting
  • Temperature: 75.0 to 82.0° F (23.9 to 27.8° C)
  • Range ph: 5.5-7.5
  • Hardness Range: 2 - 20 dGH
  • Brackish: No
  • Water Movement: Moderate
  • Water Region: Top - Marbled Hatchetfish will swim abd feed at the top of the aquarium. Notice how the mouth is at the top of the body.

Social Behaviors

Picture of a Marbled Hatchetfish

The Marbled Hatchetfish are always a good community fish. This fish is relatively shy and nervous however, so it should be spared the company of hostile tank mates. It must absolutely be kept in a school. A minimum sized school would be 6 hatchetfish, but 8 or more are ideal for it to be comfortable and settle in to aquarium life. If provided a good sized school, they will be more active and have a longer life span. Good tankmates for this fish are tetras, dwarf cichlids and Corydoras and Loricariids.

  • Venomous: No
  • Temperament: Peaceful
  • Compatible with:
    • Same species - conspecifics: Yes - They must to be kept in a school. Six fish is minimum, but 8 or more is suggested.
    • Peaceful fish (): Safe
    • Semi-Aggressive (): Threat
    • Aggressive (): Threat
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Threat
    • Slow Swimmers & Eaters (): Monitor
    • Shrimps, Crabs, Snails: Safe - not aggressive
    • Plants: Safe

Sex: Sexual differences

It is hard to tell, but if viewed from above the female is more plump and the eggs may be seen when the female is about to spawn.

Breeding / Reproduction

These freshwater hatchetfish are egg layers. Recommended breeding conditions: Ph 5.5-6.5, 5° dGH. Add peat extract to darken the water until it is almost opaque and keep the lighting subdued. Feed small flying insects to induce them to spawn. (Fruit flies or Black mosquito larvae will work).

The Marbled Hatchetfish will go through a long courtship after which the female will deposit eggs on plants and roots. The parents should be removed after spawning. The fry will hatch after 30 hours and become free swimming in 5 days. They must be fed finely powdered flake food or similar baby fish foods for the first 2 or three days but will eat baby brine thereafter. See Fish Food for Fry for information about types of foods for raising the young. For a description of breeding characin fish, see Breeding Freshwater Fish: Characins.

  • Ease of Breeding: Moderate

Fish Diseases

The Marbled Hatchetfish are hardy and disease is not usually a problem in a well maintained aquarium. That being said there is no guarantee that you won't have to deal with health problems or disease. Anything you add to your tank can bring disease to your tank. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so not to upset the balance.

A good thing about Marbled Hatchetfish is that due to their resilience, an outbreak of disease can often be limited to just one or a few fishes if you deal with it at an early stage. When keeping more sensitive types of fish, it is common for all fishes to be infected even before the first warning signs can be noticed. The best way to proactively prevent disease is to give your Flame Tetra the proper environment and give them a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. Stressed fish are more likely to acquire disease.

As with most fish the Hatchetfish are prone to skin flukes, parasitic infestations (protozoa, worms, etc.), ichthyobodo infection, parasitic infestations (protozoa, worms, etc.), bacterial infections (general), and bacterial disease. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.


The Marbled Hatchetfish is readily available and moderately priced. This freshwater hatchetfish is a less hardy species than its slightly more costly relative the Common Hatchetfish or Silver Hatchetfish Gasteropelecus sternicla. But unlike the Silver Hatchet, the Marbled Hatchet can be successfully bred in captivity.


Author: David Brough CFS, Clarice Brough CFS
Lastest Animal Stories on Marbled Hatchetfish

Tony - 2005-01-02
Marble hatchet fish caught my eye in a tropical fish store as one of the most serene fish i have ever seen before. I decided to purchase 5 of them and placed them with my 55 neon tetras in 20 gal, heavily planted tank. From the moment they were placed in the transport bag until the moment of their release into my tank i kept extreme care not to shock them, bounce them around or expose to strong light. When i arrived home i turned off the lights in my fish tank and let the open bag float for about 20 min while adding half cup of the fish tank water into the bag every five minutes. No stress is the key word for these delicate creatures if you want them to keep their immune system high. Releasing these beauties into my tank was the highlight of the day. The light being turned off contributed to their calmness and faster aclimatization to my fish tank. When the lights were turned on again [after 2 hours] they seemed relaxed, but, to my great surprise swiming in a middle portion of the tank. Next day they were swiming in their prefered area, surface, looking for some flies or mosquito larve. They accepted dried mosquito larve and frozen blood worms. It has been almost 6 months since i purchased these 5 marble hatchets and for the sake of their own peace i will give all my neon tetras away and maybe keep only 10 neons in this tank. Neons eat too fast and my hatchets have no enough time to feed well. I am planning on adding at least 3 more marble hatchets as they have become my most favorite tetra. I will attemt to breed them this summer just for the fun and the beauty of the fish keeping hobby.
Piece of advice to those who want to keep this fish: do not place the tank where little kids have access and tap on the glass. It is true that these fish are incredibly sensitive and their immune system will become weaker if they are exposed to stress. Handle them with real care and get as much information about them as possible. Good luck to all fish hobbists.

  • LoL - 2015-10-22
    Marbled hatchets are not tetras and a 20 gal is way to small for 55 neons.
Kathleen - 2010-07-27
I had a couple ( I didn't know any better, I was only 12 ) in my first aquarium many years ago and they did very well. But these are schooling fish - it's unkind to keep less than 5-6. Some people seem to equate surviving with living a good life. Most humans aren't hermits and if kept in solitary confinement are pretty miserable. What makes you think an animal that has evolved to live in social groups wouldn't be miserable without others of it's species. They swim in schools for protection from predation - on their own they must not feel fully comfortable. So even if one hatchet can survive alone I wouldn't do it to them.
And I feed live foods to improve their quality of life also. There are some pretty good flake/pellet foods available now but I feel my fish enjoy live foods.

  • my own - 2010-11-15
    What is a hatchet fishes favorite defense?
    A hatchet! hahahaha! Hope you like the joke!
Myrtle - 2009-03-27
I have over 37 fishies in my hugomongous tank. I only have 1 marble hatchet and he loves to eat spaghetti sauce flakes. I purchase them at my best friends store. It has dehydrated tomatoes in it. My fishies do NOT eat mosquito larve OR bloodworms. These fishies go with the flow and don't really need special attention. I believe it is a true waste to buy mosquito larve or bloodwoms. All my marble hatchets that I've had have lived at least 4 years. My daughter brought her favorite one, 007 to college with her. He is still living in her dorm room. Oh gawrsh I miss them so much. Anywho, these fishies are the easiest fishies I have ever had. Also, they don't really need to be in groups of 5 or more. Just one can live on it's own, like my elderly grandmother. DO NOT WASTE YOUR HARD-EARNED MOOLAH ON EXTRA SPECIAL CARE OR FOOD! I'M TELLING YOU PEOPLE IF YOU SPEND EXTRA CA-CHING ON THESE FISH YOU ARE INSANE! Thank ya'll sweeties.

  • friend - 2010-11-15
    You talk sense, good job.
Lauren - 2007-09-24
I have had really bad trouble with my fish, he keeps attacking my other fish and everything that is in the tank. Apart from that he is really good

  • wendy79 - 2011-06-15
    What kind of fish do you have? What is your tank enviroment like?
  • Charlie Roche - 2011-06-17
    You might want to remove the one fish and put him in another tank. What is the kind of sih that is attacking? He might not be a community fish or get along with others.