Hatching & Growing Brine Shrimp (Artemia) for Fishkeeping and Aquariums

Once marketed in comic books as "Sea Monkeys, brine shrimp, scientifically known as Artemia, are small crustaceans widely used in fishkeeping as a nutritious live food for aquarium fish, particularly for fry and species requiring small, protein-rich prey. Their ease of hatching, high nutritional value, and adaptability make them a staple in the aquaculture and aquarium trade. This article provides a comprehensive guide to hatching and growing brine shrimp in the context of fishkeeping, focusing on practical techniques, environmental requirements, and nutritional considerations. 

The genus Artemia (family Artemiidae) includes a small number of species adapted to hypersaline environments worldwide. Taxonomy within the genus is complex due to morphological similarities and genetic variation, but current research identifies the following species based on genetic, reproductive, and ecological differences (Browne & Bowen, 1991; Asem et al., 2010):

Artemia franciscana

• Native to the Americas, particularly North and South America. 
• Found in hypersaline lakes and salt pans, such as the Great Salt Lake (Utah, USA) and San Francisco Bay salt ponds. 
• The most commonly used species in aquaculture and fishkeeping due to its high cyst availability and hatching efficiency.  

Artemia monica  

• Endemic to Mono Lake, California, USA.
• Adapted to the unique alkaline and hypersaline conditions of this lake. 
• Not widely used in aquaculture due to its restricted range and specific environmental needs. 

Artemia persimilis

• Native to South America, primarily found in Argentina and Chile.
• Occurs in coastal lagoons and inland salt lakes.
• Less common in aquaculture but studied for its genetic distinctiveness.

Artemia sinica

• Native to East Asia, particularly China and Mongolia. 
• Found in inland saline lakes and salt pans. 
• Used in aquaculture in Asia and increasingly studied for its cold tolerance.

Artemia tibetiana  

• Found in high-altitude saline lakes on the Tibetan Plateau, China.
• Adapted to extreme conditions, including low temperatures and high UV radiation.
• Rarely used in aquaculture but of interest for ecological and genetic research.

Artemia urmiana

• Native to Lake Urmia, Iran, and possibly other saline lakes in the Middle East.
• Occurs in highly saline, fluctuating environments.
• Occasionally used in regional aquaculture and studied for its resilience.

Parthenogenetic Artemia populations

• Some Artemia populations, particularly in Europe, Asia, and Africa, reproduce parthenogenetically (asexually) and are not assigned to a specific species.
• These populations, often referred to as Artemia parthenogenetica, are found in places like the Mediterranean, Central Asia, and Australia.
• They are considered a "species complex" rather than a distinct species due to genetic variability (Asem et al., 2010).

Notes on Taxonomy

The classification of Artemia has evolved with genetic studies. Older literature often lumped many populations under Artemia salina, but molecular analyses have clarified distinct species (Browne & Bowen, 1991). Artemia salina is now more narrowly defined as a species primarily from Mediterranean Europe, though introduced populations exist elsewhere. Parthenogenetic populations complicate taxonomy, as they may share traits with bisexual species but differ in reproductive mode.

Relevance to Fishkeeping

In fishkeeping and aquaculture, Artemia franciscana dominates due to its widespread availability and reliable cyst hatching. Other species, like A. sinica or A. urmiana, are used regionally but are less common in the global aquarium trade. Parthenogenetic strains are occasionally used but less frequently due to variable cyst quality.

Why Brine Shrimp in Fishkeeping?

Brine shrimp are an excellent food source for many aquarium fish, including bettas, guppies, tetras, and marine species, as well as for rearing fry. Their nauplii (newly hatched larvae) are tiny, typically 400–500 micrometers, making them ideal for small-mouthed fish and juveniles (Lavens & Sorgeloos, 1996). Brine shrimp are rich in protein (approximately 50–60% dry weight) and essential fatty acids, particularly when enriched, enhancing fish growth and coloration (Sorgeloos et al., 2001). Additionally, their movement in the water column triggers feeding responses in predatory fish, making them more appealing than frozen or flake foods.

In fishkeeping, brine shrimp are primarily used in two forms: newly hatched nauplii for fry and small fish, and adult shrimp for larger species. Hatching brine shrimp at home is cost-effective and ensures a fresh, live food supply, while growing them to adulthood requires more effort but provides a larger food source.

Hatching Brine Shrimp

Hatching brine shrimp is a straightforward process that requires minimal equipment and careful attention to environmental conditions. Below is a step-by-step guide based on established aquaculture practices (Lavens & Sorgeloos, 1996; Treece, 2000).

Equipment Needed:

• Hatching container: A 1–2 liter plastic bottle, cone-shaped container, or specialized hatchery with a transparent body for monitoring.
• Aeration system: An air pump with airline tubing to provide gentle aeration, keeping cysts in suspension and maintaining oxygen levels.
• Light source: A small LED or desk lamp to attract nauplii during harvesting.
• Thermometer: To monitor water temperature.
• Brine shrimp cysts: High-quality cysts with a hatching rate of 80% or higher (available from aquarium suppliers).
• Non-iodized salt: Pure sea salt or marine aquarium salt for preparing saline water.
• Dechlorinated & dechlorimed water: Tap water treated or filtered to remove chemicals.
• pH buffer (if required): Baking soda to stabilize pH if needed.

Hatching Procedure

• Prepare the saline solution: Mix 25–35 grams of non-iodized salt per liter of dechlorinated water to achieve a salinity of 25–35 ppt (parts per thousand), roughly 1.018–1.025 specific gravity. This mimics the natural hypersaline environment of Artemia (Lavens & Sorgeloos, 1996).
• Set up the hatchery: Fill the hatching container with the saline solution, leaving some headspace. Add 1–2 teaspoons of brine shrimp cysts per liter of water. Overcrowding reduces hatching efficiency, so avoid adding too many cysts.
• Aerate the solution: Connect the air pump to provide gentle, continuous aeration. This prevents cysts from settling and ensures adequate oxygen (Treece, 2000).
• Maintain optimal conditions:
  • Temperature: Keep the water between 25–30°C (77–86°F). Use an aquarium heater or place the container in a warm location.
  • pH: Maintain a pH of 8.0–8.5. If the pH drops below 7.5, add a pinch of baking soda.
  • Lighting: Provide moderate light (natural or artificial) for 24 hours to stimulate hatching.
• Wait for hatching: Hatching typically takes 18–36 hours, depending on cyst quality, temperature, and salinity. Nauplii are orange and highly active, easily distinguished from unhatched cysts and empty shells.

Harvesting Nauplii

Once hatched, nauplii must be separated from unhatched cysts and debris:

• Turn off the aeration and let the solution settle for 5–10 minutes. Empty cyst shells float, unhatched cysts sink, and nauplii swim toward light.
• Place a light source near the bottom of the container to attract nauplii.
• Siphon or pour the nauplii-rich water through a fine brine shrimp net (100–200 micrometers) or coffee filter, rinsing them gently with fresh dechlorinated water to remove excess salt.
• Feed the nauplii immediately to fish or store them in clean, aerated saltwater at 10–15°C (50–59°F) for up to 24 hours to slow metabolism (Lavens & Sorgeloos, 1996).
• Freeze any leftover shrimp for later use.

Growing Brine Shrimp to Adulthood

While nauplii are ideal for fry, growing brine shrimp to adulthood (1–2 cm) provides a larger food source for adult fish like cichlids or marine species. Growing Artemia requires more space, time, and attention to water quality and feeding (Sorgeloos et al., 2001).

Setup for Growing

• Tank: Use a 5–20 gallon aquarium or container with aeration and a heater.
• Salinity: Maintain 30–35 ppt, similar to hatching conditions.
• Temperature: Keep at 25–28°C (77–82°F).
• Filtration: A sponge filter or gentle aeration prevents debris buildup without harming shrimp.
• Lighting: Provide 12–16 hours of light daily to support algae growth or feeding.

Feeding

Adult brine shrimp are filter feeders, consuming microalgae, yeast, or commercial feeds. Common options include:

• Microalgae: Nannochloropsis or Tetraselmis cultures provide optimal nutrition but require a separate culturing setup (Treece, 2000).
• Dry feeds: Active dry yeast or spirulina powder, fed sparingly (0.1–0.2 grams per liter daily) to avoid fouling the water.
• Commercial Artemia feeds designed for brine shrimp.

Feed small amounts multiple times daily, ensuring the water remains clear. Overfeeding leads to poor water quality and shrimp mortality.

Maintenance

• Perform 10–20% water changes weekly with fresh saline water to maintain quality.
• Monitor ammonia and nitrite levels, keeping them near 0 ppm.
• Brine shrimp reach adulthood in 2–3 weeks under optimal conditions, growing to 8–12 mm (Sorgeloos et al., 2001).

Harvesting Adults

Use a coarse net to collect adult shrimp. Rinse them in fresh water before feeding to fish to remove salt and debris. Adults can be fed live or frozen for later use.

Nutritional Enrichment

To maximize their value as fish food, brine shrimp can be enriched with essential fatty acids like omega-3s (DHA and EPA), critical for fish health and fry development. Enrichment involves feeding nauplii or adults with lipid-rich products for 6–12 hours before harvesting (Lavens & Sorgeloos, 1996). Enriched brine shrimp significantly improve fish growth rates and survival, particularly for marine species.

Common Issues and Solutions

• Low hatch rates: Check cyst quality, salinity, temperature, or pH. Use fresh, high-quality cysts from reputable suppliers.
• Water fouling: Reduce feeding and increase water changes when growing adults.
• Nauplii mortality: Ensure gentle aeration and avoid overcrowding during hatching.

Conclusion

Hatching and growing brine shrimp (Artemia salina) is a practical and rewarding practice for fishkeepers, providing a nutritious live food for aquarium fish. By following proper hatching techniques and maintaining optimal conditions, hobbyists can produce a steady supply of nauplii or adult shrimp tailored to their fish’s needs. Enrichment further enhances their nutritional value, supporting healthy fish growth and vibrant colors. With minimal equipment and attention to detail, brine shrimp cultivation is an accessible skill for aquarists of all levels.

References

• Lavens, P., & Sorgeloos, P. (1996). Manual on the Production and Use of Live Food for Aquaculture. FAO Fisheries Technical Paper 361. Food and Agriculture Organization of the United Nations.
• Sorgeloos, P., Dhert, P., & Candreva, P. (2001). Use of brine shrimp, Artemia spp., in marine fish larviculture. Aquaculture, 200(1–2), 147–159.
• Treece, G. D. (2000). Artemia production for marine larval fish culture. Southern Regional Aquaculture Center Publication, No. 702.
• Asem, A., Rastegar-Pouyani, N., & De Los Ríos, P. (2010). The genus Artemia Leach, 1819 (Crustacea: Branchiopoda): True and false taxonomical descriptions. Latin American Journal of Aquatic Research, 38(3), 501–514.
• Browne, R. A., & Bowen, S. T. (1991). Taxonomy and population genetics of Artemia. In R. A. Browne, P. Sorgeloos, & C. N. A. Trotman (Eds.), Artemia Biology (pp. 221–235). CRC Press.