How enrichment transforms a simple Artemia nauplii into a powerhouse of nutrition for marine aquaculture

In marine hatcheries across the world, Artemia nauplii are the live feed of choice for the delicate first stages of fish and crustacean larvae. Easy to hatch and handle, the offer reliability and availability unmatched by most other live feeds. But there is a catch: in their natural state, Artemia are nutritionally incomplete.

That is why enrichment has become a cornerstone of modern hatchery management. Without it, survival and growth rates of larvae are often compromised. As one recent review in Reviews in Aquaculture explains, “effective enrichment of Artemia not only enhances the nutritional value of the live feed but also plays a crucial role in supporting larval development, immunity, and overall aquaculture productivity.”

Newly hatched Artemia contain little of the highly unsaturated fatty acids (HUFA) that marine larvae need, especially DHA and EPA. Deficiencies in these essential fatty acids can translate into deformities, reduced growth, weak immunity and poor survival. Enrichment transforms Artemia from a convenient live feed into a true nutritional package.

Beyond lipids, hatcheries increasingly enrich with vitamins (such as C and E), amino acids like taurine, and even probiotics. Each of these plays a role: boosting stress resistance, improving digestion, or helping larvae cope with pathogenic bacteria.

Which is the best protocol?

Although no universal “recipe” exists, successful enrichment protocols share common features that have been refined over years of practice and research. Timing is critical. Nauplii begin feeding at the Instar II stage, usually six to eight hours after hatching, and this is the ideal window to start the enrichment process. At this moment, their metabolism is active and they are able to ingest the nutrients that will later be passed on the larvae.

The choice of enrichment medium is equally important. Commercial emulsion rich in DHA and EPA remain the backbone of most hatchery protocols, ensuring that Artemia deliver the essential fatty acids that larvae cannot synthetise on their own. In some facilities, microalgae such as Schizochytrium or Isochrysis are also used successfully to boost the nutritional profile.

Duration and control determine the efficiency of the process. The “sweet spot” lies between 12 and 24 hours. If enrichment is too short, Artemia will not have absorved enough nutrients; if prolonged, the organisms risk oxidising or consuming the very compounds that make them valuable.

Finally, the surrounding conditions must be carefully optimised. Aeration ensures a constant suspension of particles, while salinity between 25 and 30 parts per thousand and temperatures ranging from 25 to 28 ºC privde the stability required for maximum nutrient uptake. Continuous light keeps the Artemia active and feeding throughout the procedure.

From the theory to Practice

In a hatchery tank, the process is simple but precise. Nauplii are rinsed and transferred to clean water. Stocking density is typically 200-300 per mililitre. The chosen enrichment medium is added gradually, while aeration ensures that particles remain suspended and available for ingestion.

After the enrichment period, Artemia are harvested, rinsed, and fed immediately to larvae. Delays at this stage mean nutrient degradation and wasted effort.

Researchers stress that standarisation remains a challenge. Each hatchery, species and production system may require adjustments. But the principle is clear: enriched Artemia are not optional, they are essential for high-quality larval rearing.

For professionals in the field, the message is straightforward: treat Artemia enrichment as a critical process, not an afterthought. When done right, it is one of the most cost-effective investments a hatchery can make.