Care guide for annual killifish: characteristics of Nothobranchius and related species, diapause egg storage management, hatching techniques, and the full breeding cycle.
Key Takeaways
Care guide for annual killifish: characteristics of Nothobranchius and related species, diapause egg storage management, hatching techniques, and the full breeding cycle.
"Annual killifish" (年魚, *nengyō*) or "killifish" are a special group of tropical fish that inhabit temporary water bodies and seasonal ponds in Africa and South America, where the rainy and dry seasons are clearly defined. While all adult fish die during the dry season when the water dries up, eggs laid in the bottom substrate survive in a dormant state within the dried soil and hatch when the next rainy season arrives—an extraordinary life cycle.
They are called "annual fish" because they complete their entire life cycle within one year. Representative species include Nothobranchius (African species), Fundulopanchax, and Austrolebias (South American species). Many species have extremely vivid body colors, and the coloring of males rivals the beauty of precious gems.
Appeal: - Although their lifespan is short (6–18 months), they grow rapidly, allowing you to experience the entire cycle from hatching to spawning in just 3–4 months - You can enjoy a unique spawning process—hatching dormant eggs—that other tropical fish cannot offer - Some species have exceptionally beautiful body coloration with high ornamental value - They are relatively small (5–10 cm) and can be kept in compact aquariums
Challenges: - Their short lifespan means you must continue breeding and managing eggs to pass them to the next generation - Managing dormant eggs (temperature, humidity, storage duration) requires specific knowledge - Many species are sensitive to water quality changes, requiring regular water changes and constant monitoring
Annual killifish can be kept in small 20–30-liter aquariums. The ideal water conditions are slightly acidic to neutral (pH 6.5–7.5), with temperatures between 24–26°C. For the substrate, you can use peat moss on the bottom for spawning, or use a separate spawning box without substrate.
Basic Setup: - Small aquarium (20–30 liters) - Sponge filter (gentle water flow) - Heater (set to 25°C) - Aquatic plants (such as Egeria or hornwort)
Keeping multiple fish together is possible with the same species, but males engage in intense territorial disputes, so one male and 2–3 females in a 45-cm aquarium is ideal.
The greatest fascination of breeding annual killifish is managing and hatching dormant eggs.
Spawning: Lay moistened peat moss 3–5 cm deep on the bottom as a spawning medium. When you place a male and female together, you can observe spawning behavior (the male pushes the female into the sand). Spawning usually occurs daily.
Removing and Storing Eggs: 1. Once or twice a month, scoop out the peat moss from the spawning medium 2. Remove excess water with a paper towel (keeping moderate humidity without over-drying) 3. Place in a ziplock bag or container, and record the species, collection date, and storage period 4. Store in a dark place at 25–28°C
Dormancy Period: This varies by species, but for Nothobranchius, 2–4 months is the standard. During storage, check the condition of the eggs once a month (for mold or excessive drying).
Triggering Hatching: After the dormancy period ends, submerge the peat moss in cool, soft water (RO water or boiled water) at a temperature slightly lower than usual. Hatch at 25–26°C. If successful, fry will hatch within 24–48 hours.
Annual killifish are rarely found in pet shops—they are a specialized niche. Obtaining them from specialist breeders is the standard approach. Br-choku features breeders specializing in annual killifish, offering both breeding stock and dormant eggs. You can check storage conditions, dormancy duration, and hatching advice before purchasing. Some breeders even cater to those who want to "start with eggs first." Experience the unique world of annual killifish with their extraordinary life cycles through Br-choku.