Feeding fish with Artemia.
For feeding, Artemia is used live, dry (decapsulated), frozen, and also canned, where Artemia nauplii are kept in a special preservative solution. The Artemia crustacean at various stages of development represents one of the best types of live food for aquarium fish. Newly hatched nauplii of Artemia are used to feed the fry of almost all fish from their first days, while older crustaceans can be fed to larger fish. With a well-established maintenance method, Artemia serves as a food conveyor for fish of various species and ages.
The freshly hatched larva is not immediately freed from the eggshell. Feeding the fry is not yet possible—the shells can clog their intestines. However, the parachute stage lasts 
not long. The crustaceans free themselves from the shells and begin to move actively thanks to sharp strokes of their antennae. To detect this, it is necessary to turn off aeration. You can also illuminate one corner of the incubator. Artemia nauplii exhibit positive phototaxis and gather in the bright corner.
You can catch the larvae for feeding with a net, but it is best to do this using a rubber bulb with a glass tube inserted into it. The larvae gather toward the light, so if you bring a lighted electric lamp to one side of the crystallizer or jar, they quickly gather around it. In this way, you can also collect them for feeding fry, especially if you are not sure you can distinguish active crustaceans from parachute stages.
It is not possible to separate the crustaceans from the shells 100%. The whole issue lies in the concentration of inedible impurities. In practice, the method of draining the crustaceans is usually used. With the aeration turned off, most of the empty eggshells float, and unhatched eggs sink. The crustaceans also gather in the bottom layer, but above the layer of eggs. From there, they are collected with a thin siphon. Due to the slanted bottom, the cross-sectional area of the vessel at the level of the crustacean layer decreases, and they concentrate in a small volume of solution, from where they are easily collected. The collected crustaceans are filtered through a fine mesh net.
You can rinse the crustaceans in fresh water, but it is not mandatory. It all depends on what kind of fish needs to be fed. If this fish cannot tolerate salt, it must be rinsed. If you know that slight salinization of the water due to regular introduction of Artemia is not a problem, it is better not to rinse. In this case, the crustaceans will remain alive longer. Artemia nauplii can live in fresh water for 6-8 hours. Of course, this period is quite sufficient for the fry to eat them. In salt water, the larvae live, growing slightly, for about two weeks.
If necessary, you can grow the crustaceans further by adding baker’s yeast until the medium becomes cloudy, or microalgae. After 4-6 days, you can start feeding grown crustaceans only to adult fish. Canned Artemia deserves special mention; its nutritional properties are akin to live Artemia. The special solution in which the hatched and canned Artemia nauplii are located allows Artemia to be preserved in an almost pristine state for a long time. Canned Artemia can satisfy the needs of fish fry of almost any size, as it is produced in a wide range of nauplii sizes.
Indicators of good quality frozen Artemia are: rich red-brown color, integrity of most crustaceans, ease of “scattering” upon thawing. If a certain sliminess is observed upon thawing, this only indicates poor quality of this food, i.e., that some of the crustaceans were dead before freezing or that this Artemia had already been thawed and refrozen. A dark or almost black color of frozen crustaceans also indicates their very low quality.
Hatched Artemia is stored at a temperature of 1-4 degrees. Storage at room temperature and high stocking density leads to significant mortality of crustaceans within a few hours, especially with insufficient aeration. The refrigerator ensures a 90% survival rate of crustaceans for 48 hours.
Branchiopod crustaceans, freshwater fairy shrimp.
Among the freshwater relatives of Artemia, clam shrimp—pink Cyzicus, Leptestheria, and the half-centimeter Lynceus—typical inhabitants of puddles, are of nutritional interest. Adult crustaceans feed on detritus, small plankton, and alga-eating larvae. Of great importance should be the cultivation of those species of fairy shrimp whose development begins at low temperatures: Branchinecta paludosa, Polyartemia forcipata.
Streptocephalus torvicornis is a fairy shrimp. A freshwater relative of Artemia. It inhabits temporary water bodies of the steppe part of Ukraine, Volgograd, and Saratov Oblasts. In appearance, streptocephals are very similar to Artemia, but they are noticeably larger and reach a length of 30 mm, whereas Artemia in adulthood does not exceed 15 mm. Streptocephals, like all branchiopod crustaceans, are dioecious. Males differ from females in that their antennae, located on the head, are greatly elongated, have additional branches, and are often complexly twisted. In females, they are short and leaf-like expanded. In addition, egg sacs are clearly visible in females.
The young have a pale pink color, adult individuals have a greenish or orange-brown color, and starving crustaceans turn white with black spots on their thoracic legs. Its abdomen lacks appendages and consists of 9 segments (in Artemia there are 8). Reproduction is sexual. At a temperature of 20°C, crustaceans reach sexual maturity at the age of about three weeks from hatching. During life (over 2-2.5 months), the female lays 25-27 portions (in the first ones 15-120, later up to 600 eggs). The interval between clutches is 5-7 days. Sexually mature crustaceans and eggs are harvested in the summer-autumn period.
As is known, Artemia nauplii can live in fresh water for only a few hours. Uneaten by fry, they die and worsen the hydrochemical parameters of the water in the aquarium. Nauplii of streptocephals compare favorably with Artemia nauplii; firstly, they can live and develop in fresh water, and secondly, their hatching is gradual, right in the aquarium with the fry. And finally, being filter feeders, grown streptocephalus nauplii very effectively clean the water from bacterial turbidity.
Streptocephalus eggs are round, with a diameter of about a quarter of a millimeter. The egg shell is dense, heavily wrinkled, and colored brown. Spawned eggs always sink to the bottom. For incubation, you can take either fresh eggs from the bottom of the water body or dried ones for storage. The development of dry eggs begins from the moment they are immersed in water. Streptocephals are cultivated in crystallizers or aquariums with fresh soft water at a layer of 30-40 cm. Eggs should cover no more than 1 cm of the bottom surface. Optimal conditions: dH 2-6°, pH 6.8-7.2, T 15-20°C (max. 25°C).
The first larvae hatch in 1.5-2 days, mass emergence occurs on the 4th-7th day. Like Artemia salina nauplii, they move towards a light source. Food for them will be bacterial, yeast cells (0.1-0.5 million/ml), Chlorella, protococcal algae (0.5-0.8 million/ml). After adding algal paste, the water turns salad-green. Yeast is diluted to the consistency of diluted milk and applied with a pipette—2 drops/ml, or 4 cm3 per 100 l. On the 5th day of life, the size of the crustaceans is about 2 mm, on the 15th—up to 9 mm, on the 25th—up to 16 mm.
Streptocephals are very sensitive to lack of food. Even short-term starvation leads to their death. Starving crustaceans become almost white, often with black spots on the thoracic legs (spots always indicate unfavorable nutritional conditions). With a sufficient amount of food, crustaceans stay in the water column; with a deficiency, they sink to the bottom and stir up silt with their legs. Maturation of crustaceans occurs on the 25th-35th day; their density during this period should not be more than 25-75 spec./l. Separation of eggs from excrement is easily accomplished by stirring or centrifugation. To extend the lifespan of eggs during long-term storage, drying is carried out in silt or on quartz sand.
Cladocera (Water fleas). Daphnia – Daphnia.
Methods of breeding Artemia. Artemia incubator. 
