Best Live Food for Killifish — The Live-Food Specialists

If any group of fish was built for live food, it is the killifish. These small, often spectacularly coloured egg-layers are intense micro-predators — in the wild they hunt insect larvae, small crustaceans, and worms in everything from permanent streams to seasonal pools — and many of them will flatly refuse dry food, or accept it only grudgingly. For killifish, live food is not an enhancement; it is frequently the core of the diet. The good news is that killifish are small and their live-food needs map perfectly onto the cultures every breeder already keeps: microworms, baby brine shrimp, daphnia, and small scuds. This guide covers the best live foods for killifish and their fry.

Why Killifish Need Live Food

Killifish are obligate-leaning carnivores with a strong, movement-triggered feeding response and, often, a stubbornness about food: many species simply do not recognise static pellets or flake as food and will ignore them. Live, moving prey switches on their hunting instinct immediately. Beyond acceptance, live food delivers the protein and carotenoids that fuel killifish's famously vivid color and bring them into the condition needed for their prolific breeding. For a fishkeeper, the practical reality is simple — keep killifish, keep live food cultures.

The Best Live Foods for Killifish

Baby brine shrimp is the killifish staple — readily taken by virtually all species, ideal for color and conditioning, and the primary food for fry and juveniles. Many killie keepers feed BBS as a daily mainstay.

Microworms suit the smaller killifish species and are a key fry food; see Microworms.

Daphnia provides a lighter, digestion-friendly food for adults; see Daphnia.

Small scuds work for the larger killifish species as a high-protein option; see Scuds.

Mosquito larvae, from a safe fishless source, are a natural prey killifish hunt avidly and an excellent conditioner.

Color and Conditioning

Killifish are kept above all for color, and live food is the dietary engine behind it. Carotenoid-rich prey — baby brine shrimp especially — intensifies the metallic blues, fiery reds, and golds that make killies so striking, in a way dry food never matches. For breeding, killifish are prolific when conditioned, and a steady live diet keeps them in continuous spawning condition. Because many killies breed readily and often, the live-food supply is effectively the breeding program.

Breeding and Fry: Two Killifish Strategies

Killifish breeding splits into two broad types, and both rely on live food for the fry:

• Non-annual / plant-spawners (e.g. many Fundulopanchax, Aphyosemion) lay eggs among plants or spawning mops, hatching in a couple of weeks. Fry are small and take microworms and baby brine shrimp from the start.
• Annual killifish (e.g. Nothobranchius) lay eggs in substrate that, in the wild, dries out between rainy seasons; their eggs undergo a diapause and hatch when re-wetted. Their fry grow explosively fast and need heavy live feeding — baby brine shrimp in quantity — to keep up with their rapid development.

In both cases the fry-feeding logic follows the standard ladder — microworms and infusoria first for the smallest, then heavy baby brine shrimp — detailed in Best Live Food for Betta Fry. Annual killie fry in particular reward a constant, generous BBS supply with remarkable growth speed.

Why Cultures Matter So Much for Killies

Because killifish lean so heavily on live food and breed so readily, keeping live cultures running continuously is essential rather than optional. A killie keeper without a brine shrimp hatchery and a microworm culture is a killie keeper who will struggle to feed both adults and the steady stream of fry. This is the group where the live-food-culture habit pays off most directly. Blackwater Aquatics ships live microworm, daphnia, and scud cultures across Canada, and the Live Food Encyclopedia covers the full landscape, including how to keep these cultures producing.

Frequently Asked Questions

What is the best live food for killifish?

Baby brine shrimp is the killifish staple — readily taken by nearly all species, ideal for color and conditioning, and the primary food for fry and juveniles. Microworms suit smaller species and fry, daphnia provides a lighter digestion-friendly food, small scuds work for larger killies, and mosquito larvae are a superb natural conditioner. Killifish lean heavily on live food, so keeping cultures running is essential.

Will killifish eat flake or pellets?

Many killifish refuse dry food or accept it only grudgingly, because they are intense micro-predators whose feeding response is triggered by moving prey. Some individuals can be trained onto quality frozen or prepared foods, but live food is the reliable core of a killifish diet. For most keepers, baby brine shrimp and microworms are the dependable staples.

What do killifish fry eat?

Killifish fry take microworms and infusoria first (for the smallest) and then heavy baby brine shrimp, which drives fast growth. Annual killifish fry in particular grow explosively and need a constant, generous supply of baby brine shrimp to keep up with their rapid development. The standard fry-feeding ladder applies, with live cultures kept ready before the eggs hatch.

Does live food improve killifish color?

Yes, dramatically. Carotenoid-rich live foods, especially baby brine shrimp, intensify the metallic blues, reds, and golds that killifish are prized for, far beyond what dry food achieves. Combined with clean water and low stress, a live-food diet brings out the full, vivid color killifish are capable of.

Do I need live cultures to keep killifish?

Effectively, yes. Because killifish rely so heavily on live food and breed so readily, keeping live cultures — a baby brine shrimp hatchery and a microworm culture at minimum — running continuously is essential to feed both adults and the steady supply of fry. Killifish are the group where the live-food-culture habit pays off most directly.