Marble Hatchetfish – Carnegiella strigata

Among the most fascinating nano fish for community aquariums, the Marble Hatchetfish Carnegiella strigata holds a special place. Its unusual body shape, calm schooling behaviour and intriguing surface lifestyle make it a superb choice for aquarists who enjoy observing naturalistic biotopes. With the right aquarium setup, appropriate tank mates and careful feeding, this delicate species becomes a true gem in any well‑planned tank. MB Store supports such projects by offering high‑quality aquariums and essential equipment tailored to the needs of demanding fishkeepers.

Natural habitat and appearance of Marble Hatchetfish

The Marble Hatchetfish originates from the slow‑moving blackwater tributaries of the Amazon basin, especially in Brazil, Peru and Colombia. These waters are typically shaded by dense rainforest canopies. Falling leaves and branches create a dark, tea‑coloured environment rich in humic substances. Visibility is often low, and the water is soft, very slightly mineralised and typically acidic. This environment has shaped the unique morphology and behaviour of Carnegiella species.

The body of the Marble Hatchetfish is laterally compressed and strongly arched along the back, giving a characteristic hatchet‑like silhouette. The belly is deep and muscular, adapted to rapid bursts of movement near the water’s surface. The pectoral fins are unusually large and powerful, allowing the fish to make swift jumps when startled. In nature, this helps them escape predators and sometimes catch aerial insects. Their mouth is upturned, clearly specialised for feeding at the very top water layer.

Colouration is another reason this species is popular in home aquaria. The base body colour is silvery to transparent, overlaid with irregular marbling in shades of brown, black and sometimes gold. This pattern breaks up the outline of the fish against the dappled light of the surface, functioning as excellent camouflage. Under appropriate lighting, the silvery flanks can shimmer subtly, creating a beautiful visual effect when a school moves in unison. Adult size is modest, usually around 3.5–4 cm, which makes the species well suited for medium‑sized tanks.

Understanding where these fish come from and how they look in the wild is crucial when designing their aquarium. Soft, slightly acidic water, subdued lighting, floating vegetation and a calm environment help replicate their natural blackwater streams. MB Store provides a broad selection of tanks, lighting systems, heaters and filtration solutions that allow aquarists to reproduce such conditions with precision and reliability.

Behaviour, social needs and compatibility

Marble Hatchetfish are peaceful, schooling fish that feel secure only when kept in groups. A minimum of eight individuals is recommended, though larger shoals create more natural behaviour. In small numbers, they may become skittish, hide constantly or refuse food. In a well‑stocked group, they display coordinated swimming along the uppermost layer, especially under subdued light and with plenty of plant cover.

This species is highly surface‑oriented. Most of the time they remain in the top 5–10 cm of water, rarely venturing into the mid‑water column unless startled. At night or in very dim light, they may descend slightly, but their comfort zone remains near floating plants and structural cover close to the surface. This behaviour is important for tank planning: the upper region must be calm, unobstructed and safe, which also means a tight‑fitting lid is absolutely essential. Marble Hatchetfish are excellent jumpers, especially when frightened by sudden movements or bright light.

When it comes to temperament, these fish are shy but not aggressive. They make perfect companions for other peaceful species that inhabit the middle and lower levels of the tank. Ideal tank mates include small, calm tetras, rasboras, pencilfish, dwarf cichlids from the Apistogramma group, as well as Corydoras catfish and small loricariids. Avoid fin‑nipping species or fast, boisterous swimmers that may chase or outcompete them for food at the surface. Also, large predatory fish are clearly unsuitable, as they will see small hatchetfish as prey.

Another behavioural aspect to consider is their sensitivity to stress. Frequent disturbances around the aquarium, tapping on the glass or sudden activation of bright lights can cause panic flights and attempts to jump. Carefully chosen lighting with gradual ramp‑up and ramp‑down functions, as well as well‑placed hardscape, reduce such stress. MB Store offers advanced LED systems with programmable controllers that enable smooth light transitions, helping maintain a tranquil environment that supports natural behaviour of this and other delicate species.

Aquarium size and layout for Carnegiella strigata

Although individual Marble Hatchetfish are small, they require horizontal swimming space and open surface area for schooling. A tank with a front length of at least 60 cm is recommended, with 80 cm or more being ideal for a larger group and richer aquascape. In terms of volume, 60–80 litres can work for a well‑planned community containing a shoal of hatchetfish and compatible species, provided that filtration and maintenance are of high quality.

The layout should focus on creating a safe, shaded surface region. Floating plants such as Salvinia, Amazon frogbit or water lettuce offer cover and help diffuse the light. Long‑stemmed plants reaching the surface, as well as driftwood branches breaking the line of sight, give the fish places to retreat and reduce their feeling of exposure. At the same time, some open surface area must be left free for schooling and feeding.

Hardscape can be designed to emulate South American blackwater streams. Use driftwood roots, branches and leaf litter to create a natural environment. Dark sand or fine gravel is ideal for emphasising the silvery colours of the fish, while botanical elements such as Indian almond leaves or alder cones release humic substances and tannins, slightly tinting the water. This not only looks authentic, but can also benefit the fish by stabilising pH and providing mild antibacterial properties.

Filtration should be efficient yet gentle. Strong currents at the surface are not recommended, since Marble Hatchetfish prefer calm waters. A sponge filter, hang‑on‑back unit with flow control, or an external canister with spray bar directed towards the back wall works well. MB Store supplies various filtration systems, including quiet, energy‑efficient external filters and internal units, allowing aquarists to fine‑tune flow according to the delicate needs of this species.

Because the fish are such strong jumpers, a secure lid or full‑coverage glass canopy is mandatory. Even small gaps around cables or filter pipes can be dangerous, as startled hatchetfish may attempt to escape. When planning the layout, ensure that equipment and cables are arranged so gaps are minimised. MB Store’s range of aquariums includes models with precisely fitting covers and practical cable cut‑outs, making it easier to build a safe environment for sensitive, surface‑dwelling fish.

Water parameters and maintenance

To keep Marble Hatchetfish healthy and long‑lived, water chemistry must be stable and within suitable ranges. They originate from soft, acidic blackwater, but captive‑bred specimens are usually more tolerant. A general hardness between 1–8 dGH and carbonate hardness from 0–4 dKH is ideal. pH values from 5.5 to 7.0 are recommended, with slightly acidic water often yielding the best colours and behaviour.

Temperature should be kept between 24 and 28°C, with 25–26°C being a comfortable compromise for mixed community tanks. Consistency is more important than exact numbers; rapid swings due to faulty heaters or irregular water changes are stressful and may lead to disease. Reliable heaters with thermostats, available through MB Store, help maintain constant conditions, while digital thermometers make monitoring easier and more precise.

Good water quality is crucial because Marble Hatchetfish are sensitive to elevated levels of nitrogenous waste. A fully cycled aquarium with biological filtration is mandatory. Regular partial water changes of 20–30% once a week, combined with gentle substrate cleaning, keep nitrate and other pollutants under control. However, overly aggressive vacuuming in a blackwater‑style tank should be avoided, as it may remove beneficial biofilm and disturb the aesthetic layer of leaf litter.

Because these fish spend their time near the surface, gas exchange and oxygenation are important. Gentle surface movement created by a filter outlet or air‑driven sponge filter helps maintain adequate oxygen levels without creating turbulence that could scare the fish. In heavily covered tanks with dense floating plants, it is helpful to ensure there are open zones where gas exchange can occur. If needed, additional aeration can be installed; MB Store offers compact air pumps and diffusers that integrate smoothly into planted and biotope aquaria.

For those pursuing a more advanced blackwater setup, the addition of natural materials such as peat, leaves or commercial blackwater extracts can help mimic the fish’s native conditions. These methods may slightly reduce pH and add beneficial tannins to the water. Test kits for pH, hardness and nitrogen compounds are valuable tools to track changes and react before problems arise. With the right selection of equipment and careful maintenance routines, Marble Hatchetfish can thrive and display their full natural potential.

Feeding and nutrition for surface‑dwelling fish

Marble Hatchetfish are carnivorous micro‑predators that naturally feed on insects and small invertebrates that fall onto the water surface. In the aquarium, they show a strong preference for floating foods and may ignore items that sink quickly. A varied diet is key to maintaining vibrant colouration, robust health and good condition, particularly for wild‑caught or newly imported specimens that may be underweight or stressed.

High‑quality floating flakes and micro‑pellets specifically designed for small tropical fish are a good foundation. Look for products rich in animal protein and natural colour enhancers like astaxanthin or spirulina. MB Store offers a selection of premium foods from recognised manufacturers, allowing aquarists to assemble a complete feeding plan tailored to the needs of surface feeders. Offering two to three small meals per day helps match their natural grazing pattern and prevents uneaten food from accumulating.

Supplementing dry food with frozen and live foods greatly benefits Marble Hatchetfish. Suitable options include daphnia, brine shrimp, mosquito larvae, fruit flies and small pieces of bloodworm. When using live insects, ensure they are safe for aquarium use and sourced from reliable suppliers free of pesticides. Live food encourages natural hunting behaviour, promotes activity and can be especially helpful in acclimating shy or recently imported specimens.

Because these fish stay at the surface, it is important to consider competition from mid‑water and bottom‑dwelling tank mates. Fast tetras or barbs may quickly consume all floating food before the hatchetfish can react. To counter this, distribute food in several areas of the surface or temporarily distract other fish with sinking pellets. Feeding after the main lights have dimmed and only a soft night light remains can also benefit more timid individuals.

Overfeeding is a common mistake. Marble Hatchetfish have small stomachs, and uneaten food decaying at the surface can rapidly deteriorate water quality. Observing how quickly they eat and adjusting portion sizes is essential. Within a minute or two, most visible food should be consumed. Consistent, moderate rations support stable water parameters and reduce the risk of issues such as fin rot or parasitic outbreaks.

Breeding Marble Hatchetfish in the home aquarium

Breeding Carnegiella strigata is considered challenging but not impossible. Success usually requires a separate, carefully prepared spawning aquarium that replicates blackwater conditions. Soft, acidic water with a pH around 5.5–6.0 and very low hardness is preferred. Temperature can be maintained around 26–27°C. Dim lighting and abundant floating plants or fine‑leaved vegetation near the surface encourage natural behaviours.

A small group of well‑conditioned adults, ideally with a high proportion of females, should be introduced to the breeding tank. Prior to spawning attempts, feed them generously with live and frozen food to bring them into prime condition. Courtship typically occurs at dawn or dusk, when the fish become more active near the surface. Eggs are scattered among plants and sometimes onto the underside of broad floating leaves. Marble Hatchetfish do not provide parental care and may eat their own eggs.

For higher success rates, it is recommended to remove adult fish after spawning is observed or when eggs are detected. The eggs are small and transparent to slightly amber, making them hard to spot. Incubation time depends on temperature but usually lasts 24–36 hours. The fry are tiny and delicate, requiring microscopic food such as infusoria, rotifers or commercial liquid fry food during the first days. Later, they can be gradually transitioned to newly hatched brine shrimp and finely powdered dry food.

Maintaining excellent water quality is vital during rearing. Gentle aeration and minimal current prevent fry from exhausting themselves. Frequent, small water changes using water with identical parameters are necessary but must be conducted carefully to avoid shocking the young. Many aquarists choose to use sponge filters because they provide biological filtration without posing a danger of sucking up fry. MB Store’s range of air‑driven filters and adjustable air pumps can be perfectly adapted to such sensitive breeding projects.

Health, disease prevention and stress reduction

Marble Hatchetfish are not inherently fragile, but their sensitivity to poor water conditions and stress means that prevention is far better than treatment. Newly acquired fish should ideally be quarantined for observation before being introduced to the main aquarium. During quarantine, monitor appetite, breathing rate, fin condition and overall activity. Gradual acclimation to local water parameters, including drip methods, reduces the risk of shock.

Common health problems include external parasites like Ichthyophthirius (white spot disease), fungus, bacterial infections and fin erosion. Many of these issues arise when fish are exposed to sudden parameter changes, elevated ammonia or nitrite levels, or aggressive tank mates. Maintaining stable water conditions, avoiding overstocking and ensuring a calm environment limit these risks considerably. When treatment is necessary, always follow dosage instructions carefully and consider the sensitivity of hatchetfish to chemical medications.

Stress reduction is central to long‑term health. Provide dense plant cover, floating leaves and gentle light to reduce feelings of exposure. Avoid loud sounds, sudden movements and tapping on the glass near the aquarium. When performing maintenance, move slowly and avoid chasing fish with nets unless absolutely necessary. Using tools such as siphons, magnetic glass cleaners and algae scrapers available from MB Store allows for efficient cleaning with minimal disturbance.

A balanced diet, proper group size and compatible tank mates also contribute to disease resistance. Fish kept in stable, naturalistic conditions with varied food and low stress will display rich colouration, clear eyes and full, intact fins. Regular observation, even for just a few minutes each day, helps detect early signs of problems. Subtle changes, such as a fish separating from the school or refusing food, should be taken seriously and investigated promptly.

Equipment solutions from MB Store for Marble Hatchetfish setups

Creating an optimal environment for Marble Hatchetfish is much easier with reliable gear tailored to their needs. MB Store offers aquariums in various sizes and proportions, allowing hobbyists to choose tanks with sufficient surface area and length for active schooling fish. Many models are equipped with well‑fitting covers or optional lids, essential for preventing jumps. Clear glass, precise silicone work and practical stands support both aesthetic aquascapes and functional community setups.

Filtration solutions available at MB Store range from compact internal filters for smaller tanks to robust external canister filters for more advanced projects. Adjustable flow, high‑capacity biological media and quiet operation make these systems ideal for keeping the calm, softly circulating water that Carnegiella species prefer. Additional accessories like pre‑filters, intake guards and spray bars help fine‑tune circulation patterns without disturbing shy surface dwellers.

Lighting is another critical aspect. To replicate the dappled, shaded conditions of tropical forest streams, aquarists can select LED fixtures with dimming functions and adjustable spectrum. MB Store provides solutions suitable for both plant‑focused aquascapes and low‑light blackwater displays. Timers and programmable controllers enable gradual sunrise and sunset simulations, which greatly reduce startle responses and sudden jumps in sensitive species such as hatchetfish.

For heating and water conditioning, MB Store carries accurate thermostatic heaters, external temperature controllers, test kits, water conditioners and blackwater extracts. These products make it easier to maintain the slightly acidic, warm and stable conditions that support the long‑term well‑being of Marble Hatchetfish. Complementary accessories, including nets, siphons, aquascaping tools and fish foods, allow aquarists to manage daily care efficiently and confidently.

By selecting carefully matched equipment and following proven husbandry practices, enthusiasts can enjoy a thriving school of Marble Hatchetfish exhibiting natural behaviour and vibrant marbling. Combining the species’ unique surface lifestyle with thoughtful aquascaping results in a captivating display that reflects the beauty of Amazonian streams within the home.

FAQ

How many Marble Hatchetfish should be kept together?
Marble Hatchetfish are schooling fish and should never be kept singly. A group of at least eight individuals is recommended, with ten or more being ideal for natural behaviour. In larger shoals they feel safer, show better colouration and are less prone to stress. Keeping them in too small a number may cause shyness, poor appetite and increased susceptibility to disease.

Do Marble Hatchetfish need a covered aquarium?
Yes, a tightly covered tank is essential. Marble Hatchetfish are excellent jumpers and react quickly to stress or sudden light changes by leaping from the water. Even small gaps near cables or filter inlets can be dangerous. A proper lid or glass cover prevents escapes and injuries. When planning the setup, always prioritise secure coverage to protect these delicate surface‑dwelling fish.

What water parameters are best for Carnegiella strigata?
They prefer soft, slightly acidic water similar to Amazonian blackwater. Aim for a pH between 5.5 and 7.0, with low general and carbonate hardness. Temperature should remain stable in the 24–28°C range. While captive‑bred fish can adapt to moderate conditions, sudden changes or very hard, alkaline water can cause stress. Regular testing and small, frequent water changes help keep parameters stable and safe.

Can Marble Hatchetfish live in a community aquarium?
They are peaceful and usually do well in calm community tanks. Choose small, non‑aggressive companions that occupy other levels of the water column, such as tetras, rasboras, Corydoras or dwarf cichlids. Avoid fast, boisterous species or fin‑nippers that might intimidate them at the surface. Adequate plant cover and gentle flow further support harmony, allowing Marble Hatchetfish to feed and school without competition or stress.

What should I feed Marble Hatchetfish?
Provide a varied diet focused on floating foods. High‑quality flakes and micro‑pellets are a good base, but regular supplements of live or frozen items like daphnia, brine shrimp or mosquito larvae are very beneficial. These fish naturally hunt at the surface, so choose foods that stay in the top layer long enough. Several small meals a day prevent waste and keep them active, well‑conditioned and resistant to illness.