50 eggs of Moina macrocopa (Japanese water flea)

Triops Diet: The Importance of Moina macrocopa

Triops are opportunistic omnivorous branchiopod crustaceans: they exploit all available resources by actively filtering or hunting, consuming both plant matter (single-celled algae, organic debris) and live or dead animal prey.

In their natural habitats (temporary ponds, rice paddies), Moina macrocopa (Straus, 1820), a small planktonic cladoceran measuring 0.6 to 1.8 mm, is a frequent and highly prized prey item. Its ideal size, high protein content (≈ 55-65% of dry weight), lipid content (15-25%, including essential fatty acids), and carotenoid content make it a prime food source, particularly for juvenile Triops as young as 7-10 days old and for adults. Studies show that the regular addition of live or frozen Moina significantly improves growth rate, molting frequency, and coloration in Triops (Goulden et al., 1982; Murugan & Venkataraman, 1995). Moina macrocopa is therefore a highly recommended nutritional supplement for healthy and vigorous livestock.

Learn more about the importance of Moina macrocopa in the diet of Triops...

Contents of your Moina macrocopa egg order

In the event of unfavorable conditions (drought, cold, overpopulation), Moina macrocopa switches to sexual reproduction and produces dormant eggs (or resistance eggs). Unlike parthenogenetic eggs, which hatch quickly, these eggs do not develop immediately: they are protected by a very resistant chitinous shell called an ephippia. This structure allows them to withstand desiccation, freezing, or extreme temperatures and to remain viable for several years, even decades, until favorable aquatic conditions return.

These specific eggs are designed for long-term survival and can therefore be harvested and stored.

Your order of Moina Macrocopa eggs (ephippies) includes:

• You will receive a small bag containing an egg-sand mixture (approximately 50 to 100 eggs). You will also find a sample of powdered food (spirulina) specially formulated to feed your Moina once they have hatched.

Cultivation Guide for Moina macrocopa Eggs

Start your own Japanese water flea culture with these Moina macrocopa eggs. Easy to hatch, they are an ideal source of live food for Triops (fry, or any other small aquatic animal).

Moina macrocopa is a model organism for rearing, often preferred to classic daphnias (such as Daphnia pulex) due to its tolerance to a wide range of water salinity (some species in the genus can survive in high-salt water, although they prefer freshwater) and its high reproductive capacity.

It is one of the easiest and most productive cladocerans to rear, both for hobby aquarists and aquaculture professionals.

Its life cycle is extremely rapid: it reaches sexual maturity in just 4 to 6 days and reproduces primarily through parthenogenesis (asexual reproduction), allowing its population to double at an impressive rate. In adverse conditions and under stress, it produces resistant eggs (ephippia) capable of surviving periods of drought.

Learn more about the conditions necessary for the production of ephippia for Moina macrocopa...

The culture protocol is simple

Key steps

Fill a container of approximately 1 liter with rainwater, distilled water, or spring water. To start the culture, it is recommended to use a small container, which is easier to manage. After about a week, you will need to consider a larger container (at least 10 liters).

Pour the eggs into the water. Make sure the eggs are in direct contact with the water. The first Moina may appear after 5 to 14 days, depending on environmental conditions (temperature, water quality, oxygenation).

Daphnia pulex grow and reproduce rapidly: even if the number of individuals seems limited at first, the population multiplies very quickly thanks to their parthenogenetic reproduction.

Optimal Water Conditions

To ensure successful hatching and development of your Moina, it is important to maintain specific water conditions:

• pH: The ideal pH for Moina macrocopa is generally between 7.0 and 8.0 (a value above 9.0 leads to a sharp drop in reproduction). This planktonic cladoceran prefers slightly alkaline water but can tolerate a fairly wide pH range as long as the water is free of pollutants and heavy metals.
• Temperature: The ideal temperature for hatching eggs is between 24°C and 31°C. However, good hatching rates have been observed at room temperature, around 20°C. The key is to maintain a stable temperature: therefore, avoid placing the hatching container in direct sunlight. Direct exposure could cause significant temperature variations between periods of sunlight and shade, which would be detrimental to the development of Moina.

Growing Tips

• Feed your young Moina macrocopa sparingly using algae powder (spirulina or chlorella) or dried yeast (baker's yeast - not baking powder), previously dissolved in water.
• Wait until the water runs clear before adding more food.. Excess food can cause bacterial growth and disrupt the balance of the environment.
• Thoroughly rinse the starter bag containing the egg-sand mixture to collect all the eggs and maximize your chances of hatching.

Included in your order

• An egg and sand mixture (~50 to 100 eggs)
• A small sachet of spirulina powder to start

Moina macrocopa: an ideal live food for your Triops

Moina macrocopa is considered a very high-quality live food for Triops, both for its nutritional composition and for the way it stimulates their natural predatory behaviors. It is an abundant, inexpensive, and highly nutritious live food source.

Nutritional Composition of Moina macrocopa

Protein

Several studies show that Moina macrocopa has a very high protein content on a dry matter basis, typically between approximately 55% and over 70%, depending on the culture regimen (Chlorella, Spirulina, yeast, etc.). Recent studies, for example, report average protein levels of 65–70% in M. macrocopa enriched with microalgae such as Chlorella or Spirulina, with 15–17 amino acids detected, including the 9 essential amino acids necessary for the growth of fish and crustaceans. This makes it a protein source with a density comparable to, or even greater than, that of enriched brine shrimp.

Lipids and fatty acids

The same studies show that M. macrocopa also contains a significant lipid fraction (often around 10–15% of dry matter, sometimes more depending on the enrichment protocol). These lipids include saturated fatty acids (notably palmitic acid C16:0), but also monounsaturated and polyunsaturated fatty acids, with a significant proportion of fatty acids used for energy and tissue development in fish and crustaceans.

For Triops, these lipids play a dual role:

• A readily available energy source for an animal with a fast metabolism and a short life cycle.
• Essential structural components (cell membranes, nervous system, reproduction).

Vitamins and Growth Factors

Studies on the nutritional needs of cladocerans (including Moina) show that they require and accumulate in their tissues several B vitamins (thiamine B1, riboflavin B2, niacin/niacinamide B3, pyridoxine B6, folic acid B9, pantothenic acid B5), as well as other molecules such as cholesterol, which are essential for their own growth. Depending on the food used to cultivate Moina (microalgae, yeasts, supplements), these vitamins and lipid factors are then found in the bodies of living Moina.

When a Triops consumes a whole Moina macrocopa, it ingests not only proteins and lipids, but also a "cocktail" of water-soluble vitamins and readily bioavailable steroids (such as cholesterol), which support:

• Proper metabolic function (B vitamins for energy metabolism).
• Tissue growth and renewal.
• Reproduction (role of cholesterol and steroid precursors in arthropods).

Minerals

Mineral composition analyses performed on batches of Moina macrocopa show significant levels of calcium, phosphorus, magnesium, potassium, sodium, iron, zinc, manganese, etc., in proportions compatible with the needs of Triops, crustaceans, and fish. The calcium/phosphorus ratio is generally favorable for exoskeleton mineralization and bone growth in the animals that consume them.

For Triops, which must regularly mineralize and renew their carapace and appendages during molting, this supply of calcium and phosphorus via a whole live prey is particularly well-suited.

Consuming the entire prey (tissues, hemolymph, digestive contents) provides a broader and more natural mineral spectrum than a single dry food.

Stimulation of Natural Behavior

Beyond its chemical composition, Moina macrocopa is a live food that behaves in water in a way very similar to the natural prey of Triops (cladocerans, small planktonic crustaceans).

Mobile Prey Adapted to Active Predation

Moina swims jerkily through the water column, with a "jumping" motion characteristic of cladocerans. For a Triops, this triggers:

• Active prey hunting (movement, light foraging, exploration of the bottom and water column).
• Capture behaviors (short chases, grasping with appendages, rapid ingestion).

Unlike inert foods (flakes, pellets), Moina remains alive even in the aquarium, providing constant visual and mechanical stimulation. This makes keeping them closer to natural conditions, where Triops feed on small crustaceans, larvae, and detritus in temporary pools.

Adaptation to the Morphology and Size of Triops

The size of Moina macrocopa (approximately 0.6 to 1.8 mm in adulthood) is perfectly adapted:

• To young Triops, which can capture and ingest prey of this size very early in their development.
• To older Triops, which can consume them in large quantities as "large plankton."

Unlike more agile prey such as certain copepods of the genus Cyclops, Moina remains relatively easy to capture, which reduces the energy expenditure required for predation and maximizes the net energy gain for the Triops.