Photo: ATuin-hek at English Wikipedia (CC0) — via Wikimedia Commons
Clown Killifish (Epiplatys annulatus)
A pocket-sized, surface-dwelling killifish with bold black-and-yellow bands and a vivid red-tipped tail — a nano tank showpiece that punches well above its size.
Will it live with a Clown Killifish?
We compare each fish against your clown killifish 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 22–26 °C — no size, zone or temperament conflicts.
- Keep Clown Killifish 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; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Clown Killifish 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.
- Blackwing Hatchetfish✅ CompatiblePeaceful · 3.5 cm · Medium care · 23–28 °C (73–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the top of the tank — offer enough cover so they aren't always in each other's space.
- Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
- Keep Blackwing Hatchetfish 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 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Clown Killifish 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 23–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Clown Killifish 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)
- Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Keep Clown Killifish 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.
- Crimson Red Betta✅ CompatiblePeaceful · 3.5 cm · Hard care · 24–29 °C (75–84 °F)
- Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Clown Killifish 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; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Clown Killifish 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.
- Eyespot Rasbora✅ CompatiblePeaceful · 3.5 cm · Medium care · 20–25 °C (68–77 °F)
- Compatible on the things that matter: shared water near 22–25 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
- Keep Eyespot Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Fire Red Licorice Gourami✅ CompatiblePeaceful · 3.5 cm · Hard care · 23–28 °C (73–82 °F)
- Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Keep Clown Killifish 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 22–26 °C — no size, zone or temperament conflicts.
- Keep Clown Killifish 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.
- Ghost Shrimp✅ CompatiblePeaceful · 4 cm · Easy care · 18–28 °C (64–82 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Clown Killifish 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.
- Glowlight Rasbora✅ CompatiblePeaceful · 3.5 cm · Easy care · 23–28 °C (73–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
- Keep Glowlight Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Glowlight Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Keep Clown Killifish 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.
- Golden Dwarf Barb✅ CompatiblePeaceful · 4 cm · Easy care · 18–24 °C (64–75 °F)
- Compatible on the things that matter: shared water near 22–24 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Clown Killifish 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)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Clown Killifish 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.
- Marbled Hatchetfish✅ CompatiblePeaceful · 4 cm · Medium care · 23–28 °C (73–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the top of the tank — offer enough cover so they aren't always in each other's space.
- Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Northern Glowlight Danio✅ CompatiblePeaceful · 3.5 cm · Medium care · 18–24 °C (64–75 °F)
- Both are peaceful, and their water overlaps around 22–24 °C — no size, zone or temperament conflicts.
- Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
- Keep Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Otocinclus✅ CompatiblePeaceful · 4 cm · Medium care · 21–26 °C (70–79 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Clown Killifish 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)
- Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Keep Clown Killifish 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)
- Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Keep Clown Killifish 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.
- Pygmy Corydoras✅ CompatiblePeaceful · 3.2 cm · Easy care · 22–26 °C (72–79 °F)
- Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
- Keep Pygmy Corydoras 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 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Clown Killifish 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.
- Tailspotted Oto✅ CompatiblePeaceful · 3.5 cm · Medium care · 22–27 °C (72–81 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
- Keep Tailspotted Oto 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 Clown Killifish — plant heavily and break up sight lines.
- Keep Clown Killifish 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 clearly outsizes Clown Killifish and is semi-aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Clown Killifish 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 Clown Killifish at times; give dense cover and watch them at feeding.
- Keep Clown Killifish 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.
- 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 Clown Killifish — plant heavily and break up sight lines.
- Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
- Dwarf Chain Loach⚠️ With cautionPeaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
- Keep Dwarf Chain Loach in a shoal of 6+ or it gets stressed and nippy.
- Eastern Betta⚠️ With cautionSemi-aggressive · 6 cm · Medium care · 24–28 °C (75–82 °F)
- Eastern Betta is semi-aggressive and may chase or nip the smaller Clown Killifish — plant heavily and break up sight lines.
- Watch for Eastern Betta picking off any clown killifish small enough to fit in its mouth.
- Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
- GloFish Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 21–28 °C (70–82 °F)
- GloFish Tetra is semi-aggressive and may chase or nip the smaller Clown Killifish — plant heavily and break up sight lines.
- Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
- Keep GloFish Tetra 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)
- Expect Humpbacked Tetra to harass Clown Killifish at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Clown Killifish 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 Clown Killifish 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.
- Rainbow Emperor Tetra⚠️ With cautionSemi-aggressive · 3.6 cm · Medium care · 22–28 °C (72–82 °F)
- Rainbow Emperor Tetra and Clown Killifish are close in size, but the semi-aggressive one tends to dominate — add clown killifish in a group to spread the pressure.
- Keep Clown Killifish 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.
- Serpae Tetra⚠️ With cautionSemi-aggressive · 4 cm · Easy care · 23–28 °C (73–82 °F)
- Serpae Tetra and Clown Killifish are close in size, but the semi-aggressive one tends to dominate — add clown killifish in a group to spread the pressure.
- Keep Clown Killifish 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 is semi-aggressive and may chase or nip the smaller Clown Killifish — plant heavily and break up sight lines.
- Keep Clown Killifish 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 and Clown Killifish are close in size, but the semi-aggressive one tends to dominate — add clown killifish in a group to spread the pressure.
- Keep Clown Killifish 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)
- Striped Red-Eye Puffer is aggressive and may chase or nip the smaller Clown Killifish — plant heavily and break up sight lines.
- Keep Clown Killifish 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 Clown Killifish at times; give dense cover and watch them at feeding.
- Keep Clown Killifish 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)
- Wine Red Betta and Clown Killifish are close in size, but the aggressive one tends to dominate — add clown killifish in a group to spread the pressure.
- Keep Clown Killifish 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)
- Alligator Gar (250 cm) is big enough to swallow the 3.5 cm Clown Killifish whole.
- Alligator Gar is aggressive and may chase or nip the smaller Clown Killifish — plant heavily and break up sight lines.
- Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Keep Clown Killifish 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 3.5 cm): Clown Knifefish will treat Clown Killifish as food.
- Expect Clown Knifefish to harass Clown Killifish at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Keep Clown Killifish 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)
- Size gap is too large (100 vs 3.5 cm): Fire Eel will treat Clown Killifish as food.
- Fire Eel is semi-aggressive and may chase or nip the smaller Clown Killifish — plant heavily and break up sight lines.
- Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Keep Clown Killifish 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 3.5 cm): Koi will treat Clown Killifish as food.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Clown Killifish 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 3.5 cm): Redtail Catfish will treat Clown Killifish as food.
- Redtail Catfish clearly outsizes Clown Killifish and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Keep Clown Killifish 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)
- Size gap is too large (90 vs 3.5 cm): Spotted Gar will treat Clown Killifish as food.
- Expect Spotted Gar to harass Clown Killifish 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 Clown Killifish 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)
- Wels Catfish (300 cm) is big enough to swallow the 3.5 cm Clown Killifish whole.
- Wels Catfish is aggressive and may chase or nip the smaller Clown Killifish — plant heavily and break up sight lines.
- Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Keep Clown Killifish 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 3.5 cm): Wolf Cichlid will treat Clown Killifish as food.
- Expect Wolf Cichlid to harass Clown Killifish 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 Clown Killifish 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.
Clown Killifish care specs
- Care level
- Medium
- Breeding
- Medium
- Max size
- 3.5 cm (1.4 in)
- Min tank size
- 38 L (10 gal)
- Temperature
- 22–26 °C (72–79 °F)
- pH
- 5.5–7.5
- Hardness
- 1–10 dGH
- Lifespan
- 2–4 years
- Diet
- Carnivore
- Swim level
- Top
- Group size
- 6+ (shoaling)
- Family
- Nothobranchiidae
- Origin
- West Africa — Guinea, Sierra Leone, Liberia (rainforest streams and swamps)
What is a Clown Killifish?
The clown killifish (Epiplatys annulatus) is one of the smallest and most visually striking members of its family. Adults reach only 3–3.5 cm (about 1.4 in), yet males carry a bold pattern of alternating black-and-yellow body bands and a lyre-shaped tail tipped in red, orange, and iridescent blue — a colour palette that belongs on a much larger fish. Females are more subdued, with softer banding and a rounder body, but share the same charismatic surface-skimming lifestyle.
As a true surface dweller, this species spends nearly all its time in the top few centimetres of the water column, hunting tiny invertebrates and resting under floating plant cover. Its diminutive size and preference for soft, acidic conditions make it an ideal centrepiece for a biotope-style nano or species tank. Groups of six or more bring out natural sparring displays without significant conflict.
Where do Clown Killifish come from?
Wild clown killifish are native to West Africa — Guinea, Sierra Leone and Liberia — where they inhabit shallow, heavily shaded rainforest streams, seasonal pools and swamp margins. Water is typically very soft and acidic (often pH 5.5–6.5), tinted amber by tannins from leaf litter, and either slow-moving or stagnant. Dense floating vegetation and overhanging leaves serve simultaneously as cover, hunting ground and spawning site.
Captive-bred stock, which makes up the vast majority of fish in the trade, tolerates a wider parameter range than wild individuals, but softer, slightly acidic conditions consistently produce better colour and promote natural behaviour. The wild habitat is worth replicating: floating plants, a dark substrate, tannin-stained water and low to moderate lighting.
What size tank does a Clown Killifish need?
The practical minimum is 38 litres (10 gallons). Clown killifish are group animals — a minimum group of six is recommended — and a 38 L footprint provides enough horizontal swimming space and surface area for the whole group to spread out comfortably.
Tank shape matters. Because this species lives almost exclusively at the surface, a long, shallow aquarium is more useful than a tall one; a tank 60 cm (24 in) or longer works well. Keep the water level a few centimetres below the rim, and always fit a tight-fitting lid with no gaps — clown killifish are capable jumpers.
A sponge filter or a gentle hang-on-back with a spray-bar return keeps current minimal, replicating the still or slow-moving waters of their native range.
What water parameters do Clown Killifish need?
- Temperature: 22–26 °C (72–79 °F)
- pH: 5.5–7.5, ideally 6.0–7.0 for captive-bred stock
- Hardness: 1–10 dGH — soft water is strongly preferred
The clown killifish’s native West African streams are among the softest, most acidic freshwater environments in the world. Captive-bred fish are more adaptable, but they colour up best and breed most readily in softer, slightly acidic conditions. If your tap water is hard and alkaline, a reverse osmosis blend, peat filtration, or Indian almond leaves will bring parameters into range and add beneficial tannins.
Stability is as important as exact numbers. Cycle the tank fully before adding fish, maintain weekly partial water changes of around 20–25%, and avoid sudden temperature swings — this species is more cold-sensitive than many tropical fish given its equatorial origin.
What do Clown Killifish eat?
Clown killifish are carnivores with small mouths to match their size. In the wild they hunt tiny invertebrates and zooplankton at the surface film. A varied diet of small live or frozen foods works best in captivity:
- Micro worms, banana worms — excellent staples that stay near the surface
- Daphnia and cyclops — freeze-dried or live; good for conditioning
- Baby brine shrimp (artemia nauplii) — highly nutritious treat and conditioning food
- Flightless fruit flies — surface food that triggers strong hunting behaviour
Micro-pellets or crushed flake can supplement but should not be the sole food source — many clown killifish ignore dry foods. Feed small amounts two or three times daily and remove uneaten food promptly to protect the soft, lightly buffered water.
Are Clown Killifish peaceful — and what fish can live with them?
The clown killifish is peaceful and poses no threat to fish it cannot swallow whole. Their tiny size (3.5 cm / 1.4 in maximum) means tank-mate selection is less about aggression and more about matching scale and temperament — they are easily outcompeted by larger or more assertive species.
Good companions include small, peaceful soft-water fish that occupy lower tank levels — ember tetras, chili rasboras, pygmy corydoras and similar nano species. Avoid anything large enough to eat them, fin-nippers, or fast competitive feeders that will steal food before the killifish can reach it.
Adult dwarf shrimp (cherry shrimp, neocaridina) are generally safe given the clown killifish’s small mouth, though shrimplets may be taken; dense planting reduces losses significantly. Snails are not at risk.
For a complete list of tested pairings, see Clown Killifish tank mates.
How do you tell male from female Clown Killifish?
Sexing adult clown killifish is straightforward by 8–10 weeks of age. Males develop the characteristic lyre-shaped tail with vivid red, orange and iridescent blue markings, along with brighter, more contrasted body banding. They are slightly slimmer in build.
Females are noticeably plainer — the tail is rounded rather than lyre-shaped, lacks the colourful markings, and overall colouration is paler and less contrasted. Females are also rounder through the belly, especially when carrying eggs. The difference is most obvious when a displaying male postures alongside a female.
How do Clown Killifish breed?
Clown killifish are egg scatterers that deposit adhesive eggs among fine-leaved floating plants and moss. Unlike many killifish they are not annual fish — no dry-season diapause is required — making them relatively accessible for intermediate breeders.
Conditioning the group on live foods for one to two weeks encourages spawning. Provide fine-leaved floating plants (Java moss, floating riccia) or spawning mops at the surface. Males court females with spread fins and vivid colour displays; fertilised eggs are tiny and pale, deposited one at a time into plant material. Adults will eat eggs and fry if given the opportunity, so move spawning mops to a separate rearing container or provide enough plant cover for fry to hide.
Eggs hatch in 10–14 days at around 24 °C (75 °F). Fry are very small and require infusoria or liquid fry food for the first week, then micro worms and baby brine shrimp as they grow. Small, frequent water changes with matched parameters keep mortality low.
What diseases do Clown Killifish get?
Clown killifish are hardy in appropriate conditions, but their preference for soft, acidic water creates specific vulnerabilities:
- Velvet (Oodinium) — fine gold or rust-coloured dust on the body; often introduced with new fish or live food. Quarantine all new arrivals for two to three weeks.
- Ich (white spot) — small white cysts triggered by chilling or stress. Maintain stable temperatures and avoid cold-water swings.
- Bacterial infections / fin damage — more likely in poor water quality. Soft, poorly buffered water can crash quickly if water changes lapse; consistent maintenance is the best defence.
- Wasting / refusal to feed — sometimes seen in newly imported fish. Live foods and a quiet, planted environment usually resolve this.
Health note: disease diagnosis and medication dosing are beyond the scope of a care profile. For a sick fish, confirm symptoms against a reputable veterinary or fish-health source before treating, and always dose based on actual tank volume.
How long do Clown Killifish live?
With good care, clown killifish live 2–4 years — shorter than many tropical fish of comparable difficulty, but typical of the killifish family. A well-managed group will often spawn prolifically, providing a self-sustaining population that offsets natural turnover.
Maximising lifespan comes down to water quality, diet variety and stress reduction. Stable soft-acidic water, a varied diet of live and frozen invertebrates, and a securely lidded tank will keep a group looking their best across their full natural span.
Frequently asked questions
Can clown killifish live with shrimp?
Yes — their small mouths mean adult dwarf shrimp (cherry shrimp, neocaridina) are generally safe, though tiny shrimplets may be eaten. Dense planting reduces losses significantly.
Do clown killifish need a lid on the tank?
Absolutely. Like all killifish they are skilled jumpers. A tight-fitting lid with no gaps is essential, even over a low water level or nano tank.
What you need to keep a clown killifish
The baseline is a heated, filtered 38 L+ tank: a reliable heater to hold 22–26 °C (72–79 °F), a gentle filter that won't batter a clown killifish in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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