Killifish are a diverse family of small colourful fish from around the world — over 1,250 species.
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Killifish are a diverse family of small colourful fish from around the world — over 1,250 species. Some live only a year in seasonal pools (annual killifish); others live several years. Killifish are stunningly coloured, often hard to find in shops, and require species-specific care.
Found in freshwater habitats on every continent except Antarctica and Australia. Many live in seasonal pools — eggs survive dry seasons, hatching when water returns. Captive keepers store and ship dried eggs.
Common pet species:
Most 3–10 cm. Brilliant colours and patterns — many of the most striking small fish in fishkeeping.
Variable. Males often aggressive toward each other; females and mixed-species in calm community can work. Annual species best in species-specific setups.
Small species: 40 L (10 gallon). Larger species: 75 L+. Always lidded — killifish jump.
Heavily planted, dim, blackwater conditions for many species.
Species-specific. Most prefer soft, slightly acidic water.
Carnivorous. Frozen and live foods preferred — daphnia, bloodworms, baby brine shrimp, micro worms.
Annual species: 1 year. Non-annual: 2–5 years.
Pros: brilliant colours, niche hobby with active community, fascinating biology. Cons: harder to find than community fish, species-specific care, short lifespans.
Why "killifish"? From Dutch "kil" meaning small stream — not from "killer." They are mostly peaceful.
Annual vs non-annual? Annual species evolved to complete their lifecycle in seasonal pools — eggs diapause through dry seasons. Captive keepers cycle generations through stored eggs.
Where do I get them? Specialist online breeders, killifish clubs (American Killifish Association is active). Rarely in pet shops.
How long do they live? 1 year for annuals; 2–5 years for non-annuals.
Beginner fish? Not typically — niche hobby with species-specific needs.
The Killifish — The Brief-Lived Colourful Jewel
10–11 minutes
Brilliantly coloured killifish male in display. Caption: "ONE YEAR, ALL COLOUR".
Underwater photograph of a brilliantly coloured male killifish in display, vivid red blue and yellow patterns, peat-substrate background, gentle natural lighting, 85mm lens at f/2.5, professional aquatic photography, intense colours.
Killifish are small, brilliantly coloured, often short-lived fish — beloved of specialist fishkeepers. Today: complete killifish overview.
⏱ Timestamps 00:00 Intro Hook 01:00 The Killifish Diversity 02:30 Setup: Small Species Tank 04:00 Diet: Small Live and Frozen Foods 05:30 Social: Pairs or Trios 07:00 Health: Lifespan and Stress 08:30 3 Biggest Mistakes New Owners Make 10:00 Are Killifish Right For You? 11:00 Outro
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"Killifish are tiny, brilliantly coloured tropical and subtropical fish — among the most diverse and beautiful aquarium species. Some live just a year. Some live five. All are beloved of specialist fishkeepers. Today: complete killifish overview."
"Killifish span hundreds of species across Africa, the Americas, and parts of Asia. Two main groups: Annual species — natural lifespan one season. Eggs survive dry periods in nature. Non-annual species — multi-year lifespan. More common as standard pet aquarium fish. Popular species: Aphyosemion, Nothobranchius, Fundulopanchax, Epiplatys."
"Tank: 30–60 litres for a pair or trio. Tightly fitted lid — killifish are escape artists. Filtration: gentle sponge filter. Heater: 22–26°C. Substrate: dark or peat. Dense planting and floating plants. Soft acidic water for most species."
"Killifish are micro-predators. Live: daphnia, brine shrimp, micro-worms. Frozen: bloodworms, brine shrimp, daphnia. Some accept high-quality flake."
"Most killifish do best as a pair (one male, one female) or a trio (one male, two females). Multiple males in small tanks cause aggression. Tank mates: small peaceful species in larger tanks. Many killifish kept as single-species tanks."
"Lifespan 1–5 years depending on species. Stress from inappropriate water chemistry. Ich. Find an aquatic vet."
"Mistake one: assuming all killies live one year. Many species are multi-year. How to avoid: research the species. Mistake two: no tight lid. Jump out. How to avoid: fully covered tank. Mistake three: pet-shop sources. Killifish are usually only available through specialist clubs. How to avoid: join a killifish association for quality stock."
"Checklist: 30+ litre species tank with tight lid. Live or frozen food feasible. Specialist source. 1-5 year commitment. You appreciate jewel-like rare species. Tick four — killifish are wonderful for the dedicated keeper."
"That is the killifish — brief brilliant jewel of the fish world. Next category? Comment below — final category, exotics next. Subscribe and the bell. Next week: the tarantula — the eight-legged silent companion." (End screen: subscribe button, 'watch next: Tarantula' thumbnail, channel logo)