Marbled Hatchetfish

River Hatchetfish

Family: Gasteropelecidae Marbled Hatchetfish, Carnegiella strigata, River HatchetfishCarnegiella strigataPhoto © Animal-World: Courtesy David Brough
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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 Marbled 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 by flapping their large pectoral fins to catch flying insects. They are generally accepted as being the only true "flying fish" 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. The two can be told apart by the Marbled Hachetfish's distinctive, marbled coloring and smaller size.

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, they should be kept in a quarantine tank for a couple of weeks before they are introduced to a community aquarium.

Marbled Hatchetfish are a schooling fish and should be kept in groups of 6 or more. This shy, nervous little fish needs the companionship of its own kind to be comfortable and settle in. These fish like to hang out at the surface of the water, and they are great jumpers, so keep a good top on the aquarium. These fish will appreciate some floating plants as their mouth is situated on top of their body and the Marbled Hatchetfish is 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 FishBase.org
  • 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 Colombia, Guyana, Suriname, Peru, and Brazil. They are also known as River Hatchetfish.

They are found 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

Description

The Marbled Hatchetfish is a small, deep-bodied fish with a hatchet-shaped body. This fish will generally reach about 2 inches (5 cm) in length and has a lifespan of about 2 to 5 years. They will be more active and live longer if kept in a good-sized group, ideally with 6 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. Their is mouth situated close to the top of the 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 lifespan of about 2 to 5 years. They will live longer and be more active if kept in a group of 6 or more fish.

Fish Keeping Difficulty

The Marbled Hatchetfish is moderately hardy and recommended for aquarists with some fish keeping experience. These fish often have trouble surviving in aquariums as they are very shy feeders and will not normally take dried foods. They also are very susceptible to Ich, particularly when newly imported. Quarantine them in a separate tank for 2 or 3 weeks before introducing them into a community aquarium.

  • Aquarium Hardiness: Moderately hardy - This fish is highly susceptible to ich, particularly when introduced to an aquarium. New purchases should initially be kept in a quarantine tank.
  • Aquarist Experience Level: Intermediate

Foods and Feeding

These freshwater hatchetfish are carnivores. Their mouths are situated on the top of their bodies for feeding on the surface. These fish will normally not eat anything that falls below them as they 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, Marbled Hatchetfish will generally eat all kinds of foods as long as the food is on the surface of the water. They will not survive on 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) every day. The foods fed to these fish need to stay at the surface longer than most.

  • Diet Type: Omnivore - Their diet must be 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 of size, all need some maintenance. Over time, decomposing organic matter, nitrates, and phosphate build up and 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 to 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 at least a 15-to 20-gallon aquarium. 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. Their tank should have a moderate current, which can be accomplished using a strong canister filter or powerheads. The tank should also 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. They should 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. Keep water conditions 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 and feed at the top of the aquarium.

Social Behaviors

Picture of a Marbled Hatchetfish

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

  • Venomous: No
  • Temperament: Peaceful
  • Compatible with:
    • Same species - conspecifics: Yes - They must to be kept in a school of at least 6 fish, but 8 or more is better.
    • Peaceful fish (): Safe
    • Semi-Aggressive (): Threat
    • Aggressive (): Threat
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Threat
    • Slow Swimmers & Eaters (): Monitor - Characins can out compete them for food.
    • Shrimps, Crabs, Snails: Safe - not aggressive
    • Plants: Safe

Sex: Sexual differences

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

Breeding / Reproduction

Marbled Hatchetfish are egg layers. They are not bred on a commercial basis, but they have been bred in captivity. In the aquarium, breeding can be somewhat difficult, but they can be encouraged to spawn under the right conditions. The water must be soft and slightly acidic, and they must be fed a proper diet. These are "blackwater" fish, so the addition of peat will help to darken and soften the water. They will go through a long courtship after which the female will deposit eggs on plants and roots.

Provide a separate 10- to 20- gallon breeding tank with a thin layer of gravel as a substrate. The water should be aged, soft, and slightly acidic with a pH of 5.5 to 6.5 and a hardness of about 5°. The temperature will need to be slightly elevated at around 76 to 79° F (24 - 26° C). Keep the tank dimly lit and provide floating plants. The plants will help to further reduce the light, and along with the substrate, will be used as a spawning medium. A small, air-powered sponge filter will provide filtration and gentle water circulation. Filter the water through aquarium-safe peat or mix peat into the substrate to darken the water.

They can be bred in pairs, but the most successful way to spawn these fish is in a small group of 4 to 6 individuals. Females are generally more rounded than males, and sometimes the eggs can be seen in the body cavity. Feed the breeders a rich diet that includes plenty of small flying insects, such as fruit flies, bloodworms, and other small crustaceans to induce them to spawn.

Once a successful spawn has been achieved, remove the parents as they will eat both the eggs and fry. The eggs will hatch in approximately 30 to 36 hours. The fry will be free-swimming 1 to 2 days later and are very small. The smallest foods possible, like infusoria, are needed for the first week or so until the fry are large enough to feed on microworm or brine shrimp nauplii. About 20 days after they hatch, the fry will take on the body shape of the adults and swim in all areas of the aquarium. 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 prone to developing ick (ichthyobodo infection). This is especially true when they are first introduced to an new aquarium. Newly acquired specimens should be kept in a quarantine tank before they are introduced into a community. Even so, they will still be susceptible to ick if their tank water is not kept soft and acidic.

As with most fish, these freshwater hatchetfish are prone to skin flukes, parasitic infestations (protozoa, worms, etc.), parasitic infestations (protozoa, worms, etc.), bacterial infections (general), and bacterial disease. They are extremely 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 introduce disease. 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 as 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 dealt with 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 Marbled Hatchetfish the proper environment and a well-balanced diet.

The more closely their environment resembles their natural habitat, the less stress the fish will have, making them healthier and happiery. Stressed fish are more likely to acquire disease. Aquarists should read up on 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.

Availability

Marbled Hatchetfish are 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.

References

Author: Clarice Brough CFS, David 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.
Reply
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!
Reply
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.
Reply
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.
Reply