Photo: Wikimedia Commons contributor (CC BY-SA 3.0) — via Wikimedia Commons
Marbled Hatchetfish (Carnegiella strigata)
A living surface-skimmer with a hatchet-shaped body and the ability to genuinely fly out of an open tank — keep a tight lid.
Will it live with a Marbled Hatchetfish?
We compare each fish against your marbled hatchetfish on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- African Dwarf Frog✅ CompatiblePeaceful · 4 cm · Medium care · 22–26 °C (72–79 °F)
- Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Amapá Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 24–27 °C (75–81 °F)
- Both are peaceful, and their water overlaps around 24–27 °C — no size, zone or temperament conflicts.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Amapá Tetra in a shoal of 6+ or it gets stressed and nippy.
- Black Phantom Tetra✅ CompatiblePeaceful · 4.5 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Black Phantom Tetra in a shoal of 6+ or it gets stressed and nippy.
- Blue Danio✅ CompatiblePeaceful · 4 cm · Easy care · 21–26 °C (70–79 °F)
- Compatible on the things that matter: shared water near 23–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Blue Danio in a shoal of 6+ or it gets stressed and nippy.
- Blue Emperor Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 23–27 °C (73–81 °F)
- Compatible on the things that matter: shared water near 23–27 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Blue Emperor Tetra in a shoal of 6+ or it gets stressed and nippy.
- Cardinal Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 23–27 °C (73–81 °F)
- Compatible on the things that matter: shared water near 23–27 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
- Emperor Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 23–27 °C (73–81 °F)
- Both are peaceful, and their water overlaps around 23–27 °C — no size, zone or temperament conflicts.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Emperor Tetra in a shoal of 6+ or it gets stressed and nippy.
- Flame Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Flame Tetra in a shoal of 6+ or it gets stressed and nippy.
- Glowlight Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Gold Tetra✅ CompatiblePeaceful · 4.5 cm · Easy care · 23–28 °C (73–82 °F)
- Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Gold Tetra in a shoal of 6+ or it gets stressed and nippy.
- Golden Dwarf Barb✅ CompatiblePeaceful · 4 cm · Easy care · 18–24 °C (64–75 °F)
- Both are peaceful, and their water overlaps around 23–24 °C — no size, zone or temperament conflicts.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Golden Dwarf Barb in a shoal of 6+ or it gets stressed and nippy.
- Jelly Bean Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 20–26 °C (68–79 °F)
- Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Jelly Bean Tetra in a shoal of 10+ or it gets stressed and nippy.
- Otocinclus✅ CompatiblePeaceful · 4 cm · Medium care · 21–26 °C (70–79 °F)
- Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Otocinclus in a shoal of 6+ or it gets stressed and nippy.
- Phoenix Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Phoenix Tetra in a shoal of 8+ or it gets stressed and nippy.
- Purple Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 22–26 °C (72–79 °F)
- Compatible on the things that matter: shared water near 23–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Purple Tetra in a shoal of 8+ or it gets stressed and nippy.
- Rainbow Emperor Tetra✅ CompatibleSemi-aggressive · 3.6 cm · Medium care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
- Red Phantom Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Rosy Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Rosy Tetra in a shoal of 6+ or it gets stressed and nippy.
- Rummy Nose Rasbora✅ CompatiblePeaceful · 4 cm · Medium care · 20–26 °C (68–79 °F)
- Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Rummy Nose Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Sparkling Gourami✅ CompatiblePeaceful · 4 cm · Medium care · 24–28 °C (75–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Both favour the top of the tank — offer enough cover so they aren't always in each other's space.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Strawberry Betta✅ CompatiblePeaceful · 4 cm · Medium care · 22–27 °C (72–81 °F)
- Compatible on the things that matter: shared water near 23–27 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Threadfin Rainbowfish✅ CompatiblePeaceful · 4 cm · Medium care · 24–28 °C (75–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Both favour the top of the tank — offer enough cover so they aren't always in each other's space.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Threadfin Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
- Tiger Otocinclus✅ CompatiblePeaceful · 4 cm · Medium care · 22–27 °C (72–81 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Tiger Otocinclus in a shoal of 6+ or it gets stressed and nippy.
- Yellow Phantom Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 23–27 °C (73–81 °F)
- Both are peaceful, and their water overlaps around 23–27 °C — no size, zone or temperament conflicts.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Yellow Phantom Tetra in a shoal of 6+ or it gets stressed and nippy.
- Black Darter Tetra⚠️ With cautionSemi-aggressive · 4 cm · Hard care · 21–28 °C (70–82 °F)
- Black Darter Tetra is semi-aggressive and may chase or nip the smaller Marbled Hatchetfish — plant heavily and break up sight lines.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Black Ruby Barb⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 22–26 °C (72–79 °F)
- Black Ruby Barb and Marbled Hatchetfish are close in size, but the semi-aggressive one tends to dominate — add marbled hatchetfish in a group to spread the pressure.
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Black Ruby Barb in a shoal of 6+ or it gets stressed and nippy.
- Black Skirt Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
- Expect Black Skirt Tetra to harass Marbled Hatchetfish at times; give dense cover and watch them at feeding.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Black Skirt Tetra in a shoal of 6+ or it gets stressed and nippy.
- Blue Turbo Snail⚠️ With cautionPeaceful · 5 cm · Medium care · 25–30 °C (77–86 °F)
- Different pH ranges (5.5–7 vs 7.5–8.5); doable if you sit in the shared band, but not ideal long-term.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Cherry Shrimp⚠️ With cautionPeaceful · 3 cm · Easy care · 18–28 °C (64–82 °F)
- Adult Cherry Shrimp might survive with Marbled Hatchetfish, but expect the young to be eaten — plant heavily.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Cherry Shrimp in a shoal of 10+ or it gets stressed and nippy.
- Desert Goby⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
- Desert Goby is semi-aggressive and may chase or nip the smaller Marbled Hatchetfish — plant heavily and break up sight lines.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Ghost Shrimp⚠️ With cautionPeaceful · 4 cm · Easy care · 18–28 °C (64–82 °F)
- Adult Ghost Shrimp might survive with Marbled Hatchetfish, but expect the young to be eaten — plant heavily.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Ghost Shrimp in a shoal of 6+ or it gets stressed and nippy.
- Humpbacked Tetra⚠️ With cautionSemi-aggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Humpbacked Tetra and Marbled Hatchetfish are close in size, but the semi-aggressive one tends to dominate — add marbled hatchetfish in a group to spread the pressure.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Humpbacked Tetra in a shoal of 8+ or it gets stressed and nippy.
- Morse Code Corydoras⚠️ With cautionPeaceful · 5 cm · Medium care · 23–26 °C (73–79 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Morse Code Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Serpae Tetra⚠️ With cautionSemi-aggressive · 4 cm · Easy care · 23–28 °C (73–82 °F)
- Serpae Tetra and Marbled Hatchetfish are close in size, but the semi-aggressive one tends to dominate — add marbled hatchetfish in a group to spread the pressure.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Serpae Tetra in a shoal of 6+ or it gets stressed and nippy.
- Silvertip Tetra⚠️ With cautionSemi-aggressive · 5 cm · Easy care · 22–28 °C (72–82 °F)
- Silvertip Tetra and Marbled Hatchetfish are close in size, but the semi-aggressive one tends to dominate — add marbled hatchetfish in a group to spread the pressure.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Silvertip Tetra in a shoal of 6+ or it gets stressed and nippy.
- Spotfin Betta⚠️ With cautionSemi-aggressive · 5 cm · Medium care · 23–28 °C (73–82 °F)
- Spotfin Betta is semi-aggressive and may chase or nip the smaller Marbled Hatchetfish — plant heavily and break up sight lines.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Striped Red-Eye Puffer⚠️ With cautionAggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Expect Striped Red-Eye Puffer to harass Marbled Hatchetfish at times; give dense cover and watch them at feeding.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Tiger Badis⚠️ With cautionSemi-aggressive · 4 cm · Medium care · 22–24 °C (72–75 °F)
- Expect Tiger Badis to harass Marbled Hatchetfish at times; give dense cover and watch them at feeding.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Tiger Shrimp⚠️ With cautionPeaceful · 3 cm · Hard care · 20–25 °C (68–77 °F)
- Adult Tiger Shrimp might survive with Marbled Hatchetfish, but expect the young to be eaten — plant heavily.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Tiger Shrimp in a shoal of 6+ or it gets stressed and nippy.
- Wine Red Betta⚠️ With cautionAggressive · 5 cm · Medium care · 24–28 °C (75–82 °F)
- Expect Wine Red Betta to harass Marbled Hatchetfish at times; give dense cover and watch them at feeding.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Alligator Gar⛔ Not recommendedAggressive · 250 cm · Hard care · 24–28 °C (75–82 °F)
- Marbled Hatchetfish is bite-sized to a 250 cm predatory alligator gar — it will be eaten.
- Alligator Gar clearly outsizes Marbled Hatchetfish and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Clown Knifefish⛔ Not recommendedAggressive · 90 cm · Hard care · 24–28 °C (75–82 °F)
- Size gap is too large (90 vs 4 cm): Clown Knifefish will treat Marbled Hatchetfish as food.
- Clown Knifefish clearly outsizes Marbled Hatchetfish and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Fire Eel⛔ Not recommendedSemi-aggressive · 100 cm · Medium care · 24–28 °C (75–82 °F)
- Marbled Hatchetfish is bite-sized to a 100 cm predatory fire eel — it will be eaten.
- Fire Eel is semi-aggressive and may chase or nip the smaller Marbled Hatchetfish — plant heavily and break up sight lines.
- Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Koi⛔ Not recommendedPeaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
- Size gap is too large (90 vs 4 cm): Koi will treat Marbled Hatchetfish as food.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Redtail Catfish⛔ Not recommendedAggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
- Size gap is too large (120 vs 4 cm): Redtail Catfish will treat Marbled Hatchetfish as food.
- Expect Redtail Catfish to harass Marbled Hatchetfish at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Spotted Gar⛔ Not recommendedAggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
- Marbled Hatchetfish is bite-sized to a 90 cm predatory spotted gar — it will be eaten.
- Expect Spotted Gar to harass Marbled Hatchetfish at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Wels Catfish⛔ Not recommendedAggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
- Size gap is too large (300 vs 4 cm): Wels Catfish will treat Marbled Hatchetfish as food.
- Wels Catfish clearly outsizes Marbled Hatchetfish and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Wolf Cichlid⛔ Not recommendedAggressive · 72 cm · Hard care · 24–30 °C (75–86 °F)
- Size gap is too large (72 vs 4 cm): Wolf Cichlid will treat Marbled Hatchetfish as food.
- Expect Wolf Cichlid to harass Marbled Hatchetfish at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
Compatibility is computed from each species' care data — a strong starting point, not a guarantee. Individual temperament varies, so always introduce new fish slowly and watch them.
Marbled Hatchetfish care specs
- Care level
- Medium
- Breeding
- Very Hard
- Max size
- 4 cm (1.6 in)
- Min tank size
- 60 L (15.9 gal)
- Temperature
- 23–28 °C (73–82 °F)
- pH
- 5.5–7
- Hardness
- 1–10 dGH
- Lifespan
- 3–5 years
- Diet
- Carnivore
- Swim level
- Top
- Group size
- 6+ (shoaling)
- Family
- Gasteropelecidae
- Origin
- South America — Amazon and Orinoco basins (Peru, Colombia, Brazil, Guyana)
What is a Marbled Hatchetfish?
The marbled hatchetfish (Carnegiella strigata) is one of the most anatomically distinctive freshwater aquarium fish available. Its body is laterally compressed with a dramatically deep keel — the belly curves sharply downward while the back is nearly flat — housing massively hypertrophied pectoral muscles that let the fish beat its fins fast enough to break the water surface and glide briefly through the air. This is the only aquarium species capable of true powered flight.
Adults reach 4 cm (1.5 in). The silver flanks carry irregular brown-black marbled streaks that vary between individuals. A shoal of six or more patrolling the surface of a planted tank is striking. They are fully peaceful, occupy the top zone exclusively, and make no demands on any other level of the tank.
Where do Marbled Hatchetfish come from in the wild?
Wild marbled hatchetfish range across the Amazon and Orinoco basins in Peru, Colombia, Brazil and Guyana. They inhabit the shaded surface of blackwater streams, flooded igapo forest, and slow river margins where overhanging vegetation delivers a steady supply of fallen insects and invertebrates.
The water is very soft, acidic and tannin-stained. Temperatures sit in the low-to-mid twenties Celsius and sunlight rarely penetrates the canopy. Replicating this — soft water, pH in the 6.0–6.8 range, subdued lighting, floating plants — produces bolder, more resilient fish than hard alkaline tap water ever will.
What tank size and setup do Marbled Hatchetfish need?
The minimum is 60 L (16 gal) for a school of six, but a longer footprint beats raw volume. Hatchetfish patrol horizontally; a shallow, wide tank of 80–100 L (21–26 gal) with a 60 cm (24 in) or longer run is ideal.
Essential setup points:
- Tight-fitting lid. These fish are powerful, reflexive jumpers. Even a small gap around a heater cable is enough. Mesh or solid glass/acrylic tops both work — check every gap.
- Floating plants (water lettuce, frogbit, Ceratopteris) provide the overhead cover the fish instinctively seek and diffuse harsh light. Fish with surface cover are visibly calmer.
- Gentle flow. Use a spray bar aimed at the glass or a low-turnover sponge filter — enough to oxygenate without creating a strong surface current.
- Dark substrate and background to reduce startle responses and bring out the silver-and-marble colouring.
Leave open surface lanes between plant clusters so the fish can cruise and feed freely.
What water parameters do Marbled Hatchetfish need?
- Temperature: 23–28 °C (73–82 °F); 25–26 °C suits long-term maintenance well.
- pH: 5.5–7.0; target 6.0–6.8 to reflect blackwater origins.
- Hardness: 1–10 dGH. Hard alkaline tap water above 10 dGH stresses them chronically. Blend with RO water or use Indian almond leaves and alder cones to soften and acidify naturally.
A fully cycled tank and consistent 20–30% weekly water changes are essential — marbled hatchetfish are sensitive to ammonia, nitrite and rapid water-quality swings. Do not add them to an uncycled tank.
What do Marbled Hatchetfish eat?
Marbled hatchetfish are strict surface feeders. They eat insects, larvae and small invertebrates at the waterline in nature and behave the same way in captivity — sinking foods go uneaten.
Good foods: live or frozen fruit flies (Drosophila) — a near-perfect natural match; frozen mosquito larvae; frozen brine shrimp; small floating micro-pellets as a dry-food base. Feed small amounts once or twice a day, choosing particle sizes proportional to a 4 cm fish. Remove uneaten food promptly.
How do Marbled Hatchetfish behave, and what fish can live with them?
Marbled hatchetfish are peaceful and shoaling. A minimum group of six is necessary — fewer causes chronic stress, pale colour and constant hiding. Eight to twelve produces confident, natural shoaling behaviour.
They occupy only the top zone, so they pair cleanly with mid- and lower-level community fish: cardinal tetras, rummy-nose tetras, corydoras and small loaches leave the surface entirely clear. Avoid large predators, aggressive fin-nippers like tiger barbs, and boisterous surface fish that will outcompete them at feeding time. Peaceful invertebrates are fully compatible.
See Marbled Hatchetfish tank mates for a full, filterable pairing list.
How do you tell male from female Marbled Hatchetfish?
Sexual dimorphism is subtle. Females are slightly broader across the belly when viewed from directly above, a difference that becomes more obvious in gravid fish. Males are marginally slimmer. Colour, pattern and fin shape are identical between sexes. Reliable sexing requires looking straight down on the group with good lighting and comparing belly depth — and even then, outside of spawning condition, the difference can be too slight to call.
Can Marbled Hatchetfish be bred in captivity?
Breeding is rated very hard and is rarely achieved outside dedicated setups. Conditioning adults on live foods, raising temperature to 27–28 °C (81–82 °F) and using very soft, acidic water (pH 5.5–6.5, under 3 dGH) are the conditions most associated with spawning. Eggs are scattered among fine-leaved surface plants with no parental care; adults will eat eggs and fry if not separated promptly. Fry are tiny and need infusoria or commercial fry emulsions before graduating to brine shrimp nauplii. Most fish in the hobby are wild-caught, and captive-bred stock remains uncommon. Breeding this species is a project for experienced fishkeepers with a dedicated tank.
What diseases affect Marbled Hatchetfish?
Common problems include:
- Ich: White pin-point spots and flicking; prevented by stable temperature and quarantining new arrivals.
- Bacterial infections: Opportunistic bacteria exploit wounds from lid impacts. A secure cover is the primary prevention.
- Velvet (Oodinium): Dusty gold sheen and rapid gill movement; more likely in fish kept outside correct water chemistry.
- Shipping stress: Wild-caught fish are vulnerable in their first weeks. Quarantine all new arrivals for at least two to three weeks in soft, acidic, stable water before introducing them to the display tank.
Health note: Medication dosing and disease diagnosis are outside the scope of a care profile. For a sick fish, confirm the diagnosis against a reputable fish-health or veterinary source before medicating — and address the underlying water-quality cause at the same time.
How long do Marbled Hatchetfish live?
With good care, 3–5 years. In practice, losses before that are common — most are wild-caught, making acclimation critical, and they are more sensitive to water-quality lapses than many community fish. The most preventable cause of early death is jumping; a lid with no gaps removes that risk entirely. Consistent soft, acidic water, varied surface foods and a calm tank free of aggressive tank-mates give a school the best chance of reaching its natural lifespan.
Frequently asked questions
Can marbled hatchetfish jump?
Yes — they are exceptional jumpers that use their enlarged pectoral muscles to briefly leave the water. Even a small gap in a lid is enough for them to escape, and they dry out quickly. A tight-fitting cover is non-negotiable.
What do marbled hatchetfish eat?
They are strict surface feeders that target insects and invertebrates at the waterline. Offer floating foods — small live or frozen insects (fruit flies, mosquito larvae), frozen brine shrimp, and quality floating micro-pellets. They rarely descend to eat from the bottom.
What you need to keep a marbled hatchetfish
The baseline is a heated, filtered 60 L+ tank: a reliable heater to hold 23–28 °C (73–82 °F), a gentle filter that won't batter a marbled hatchetfish in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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