Reproduction of daphnia in summer, what kind of reproduction. Description and the whole truth about water flea bites. Description and types for home breeding

Hello to all aquarists! In this publication I will tell you about live food for Daphnia fish. There are several species of daphnia, but Daphnia moina or magna are bred at home as these species are better suited for breeding than others.

Many aquarists raise their own live food. Such food can be: acetic eel and panagrel, grindal and enchytraeus, aulophorus, and even Drosophila flies. I breed Daphnia moina for my fish, and I think this is the best live food.

For those aquarists who are not familiar enough with the Daphnia crustaceans, I can suggest that they familiarize themselves in more detail with the Wikipedia material. Daphnia (lat. Daphnia) - a genus of planktonic crustaceans from the superorder Cladocera ( Cladocera). Body length - from 0.2 to 6 mm. Daphnia are sometimes called water fleas.

Cultivation of Daphnia as food is widespread, as in industrial purposes, and aquarists. In favorable conditions, daphnia reproduce and grow easily and quickly, which makes it possible to obtain 30-50 (in some cases up to 100) grams of crustaceans per day from one cubic meter of culture.

The source culture can easily be obtained from natural reservoirs. It is advisable to catch crustaceans in small bodies of water, where the daphnia population can be practically free from the admixture of other animals. IN winter time A culture of daphnia can be obtained from ephippial resting eggs, previously collected from the surface of the water or from the upper layer of silt. Collected ephippiums are well preserved in a dry state in a cool room.

Depending on the required number of crustaceans, daphnia can be cultivated both in small vessels and in large pools and ponds. The optimal density of the crop is 300-1000 g/m³. Periodically, every few weeks or months, the culture is replanted. The aging of a crop is associated with the accumulation of metabolic and decomposition products in it and with its contamination by other organisms. When changing water, the life of the crop is extended.

The optimal growing temperature is 26-29°C, the medium reaction is neutral (pH 6.8-7.8), oxygen content is at least 3-6 mg/l, oxidability is 14.8-26.2 mg O 2 /l. When growing daphnia, both joint and separate cultivation of crustaceans and food for them are used.

When grown together, add to the culture organic fertilizers, for example, manure applied in an amount of 1.5 kg/m 3. Possible to grow on mineral fertilizers, the addition of which causes the rapid development of unicellular algae. The disadvantages of co-cultivation are severe water pollution, rapid aging of the culture and rapid overgrowing of the container with filamentous algae.

Separate cultivation of daphnia and food for them does not have these disadvantages, but is technically more complex and is used mainly in conditions of mass industrial cultivation of feed crustaceans. In this case, an algal culture is grown separately, which is added to the container with daphnia 1-2 times a day.

In laboratory and home conditions, it is convenient to maintain a culture of daphnia with yeast, added daily little by little in the amount of 15-20 g per cubic meter of culture (15-20 mg/l). Standardized methods for laboratory cultivation of Daphnia are described in toxicology and bioassay manuals.

Live, dried and frozen daphnia are often used as food for aquarium fish or insects kept in terrariums. In industrial fish farming great importance has daphnia breeding for food.

Daphnia is one of the objects for testing the toxicity of aqueous solutions chemical compounds, used in pollution research aquatic environment. Daphnia are sensitive even to small concentrations of some salts; for example, the addition of copper salts at a concentration of 0.01 mg/l causes the movements of the crustaceans to slow down; they either sink to the bottom or freeze at the surface film of water.

Why is Daphnia moina better?

This species of daphnia is unpretentious and reproduces quickly, and it contains more protein than other species of daphnia. Daphnia moina is not only smaller, but also softer and can be used not only as food for adult fish, but also as a live starter food for fry, which is very important when breeding fish.

In addition, this starter food is planktonic and corresponds to natural fry food. For aquarists and fish breeders, this food is a real find.

In fact, Daphnia moina is a universal food, and its versatility lies in the fact that large crustaceans are suitable for feeding adult fish, and small fry, which are always present in large quantities in the aquarium, are suitable for feeding fry. For example, when I bred fire barbs, I added daphnia directly to the fry in the aquarium. Daphnia lived and multiplied, and the fry, eating small crustaceans, grew very quickly.

It must be said that aquarists come to live food when they start breeding fish for the simple reason that adult fish can survive on dry food, but it is usually not possible to raise fry without live food.

But not only fry, but also adult fish need live food, so if your fish’s diet consists of live food, this will have a very beneficial effect on their health and well-being. Fish that eat live food get sick less and do not lag behind in growth.

Such fish willingly go to spawn, and spawning can occur without any preparation and even in community aquarium. Live food has a calming effect on new fish when the fish are still at the stage of stress and adaptation, and for sick fish this is perhaps the only food that they do not refuse.

Daphnia moina breeding at home

I breed daphnia in a fifty liter aquarium, which is lit by one fluorescent lamp at 20 W. The duration of daylight is 8-12 hours, and the water temperature ranges from 26 to 28° degrees. You need to know that the higher the water temperature and the longer the daylight hours, the faster the daphnia reproduces and vice versa.

I feed daphnia with dry baker's yeast after dissolving it in water and adding it to the aquarium until the water becomes slightly cloudy. When the water becomes clear again, I repeat feeding. I use aeration in rare cases, for example, when it is necessary to remove a film from the surface of the water or to mix the yeast more thoroughly.

It is best to start breeding daphnia in a small container, for example, it could be a liter or one and a half liter glass jar. Why should the initial dishes be small? The point is that for not large quantity crustaceans in large volume More water and yeast will be needed, and yeast eaten by crustaceans at the wrong time may precipitate.

Of course, there is nothing particularly scary here, but it is better to maintain cleanliness since daphnia always feel better in fresh water. The water in the jar should be from a healthy aquarium that has not been used before or has not been used for a long time. medications, and if there is no such water, you can simply get by with tap water, but only without chlorine in it.

Breeding Daphnia moina is easy and simple; in fact, let me tell you and show you how it’s done. I have in my hand a bag containing a breeding of Daphnia moin, it consists of a mixture of river sand and ephippia.

Daphnia eggs

Ephippia are the eggs of daphnia. They look like small white grains that crustaceans carry on their backs and periodically drop, then from the ephippia new daphnia are born, by the way, the same small fry that are excellent as starter food for fry of many species of fish.

Ephippia can be seen at the bottom of a cultivator's aquarium or floating in a net when catching daphnia. How to get daphnia breeding in registered letter You can find out on my blog from the publication “Daphnia fish food”.

It must be said that such a layout was invented by me to send it to the northern geographical areas where daphnia is not found at all, but as statistics show, all aquarists and even aquarists from neighboring countries need this live food.

Pour the mixture into the jar and carefully stir it so that the sand is evenly distributed along the bottom of the jar. We leave the jar in a lighted place, for example, a windowsill, and wait. On the second or third day, depending on the water temperature, daphnia will be born.

Well, a day passed and on the second day daphnia crustaceans appeared. Let's start feeding.

It is necessary to wait 3 to 5 days for a larger number of crustaceans in the jar to then transplant them into the aquarium for further reproduction. Let's wait.

Well, today is the 4th day that the crustaceans in the jar have grown and given offspring and there are noticeably more of them. Let's transplant them into an aquarium for further breeding.

Daphnia in the aquarium

It should be noted that hunger is harmful for crustaceans and therefore you should always make sure that yeast is present in the water of daphnia. Let's feed the crustaceans.

A week has passed since the daphnia were transplanted into the aquarium. All these days the crustaceans were actively breeding and seemed to have completely forgotten about the cramped conditions. All this time I fed the daphnia once a day with yeast, and maintained the water temperature at 26 ° degrees. Daphnia has developed a lot and it’s time to give the fish a real feast!

It is necessary to note such important points: When catching daphnia, you should always leave a sufficient number of crustaceans for their further reproduction, since the rate of reproduction depends on the initial quantity.

Fresh water also has a beneficial effect on the reproduction of daphnia, so after about 2-3 weeks the water in the aquarium cultivator must be completely replaced, and it is more convenient to do this after the next catch of daphnia.

The need to change the water may be indicated by such factors as plaque on the glass, as well as sluggish behavior of the crustaceans, which indicates that the conditions have not changed better side, and daphnia dies, and when good conditions crustaceans are always nimble and move quickly.

Buy Daphnia moina eggs

You can buy Daphnia moina eggs for breeding at home using the link:

For many aquarium fish lovers, daphnia is used as food for the pets living in it. Its maintenance cannot be called simple, since it requires timely care proper nutrition. Now you can buy food in specialized stores. However, previously it was bought at the market or prepared independently, and planktonic crustaceans were caught in natural reservoirs.

This object has 2 eyes

Appearance and structure

Many people associate Daphnia with dry fish food. In fact, these are small crustaceans that live in all standing continental reservoirs. They belong to the genus of planktonic crustaceans. Another common name is water flea.

Cladocerans called daphnia usually have two eyes on their heads. However, sexually mature individuals can sometimes be distinguished by one double eye and an additional eye located close to it. It is the unpaired organ that is responsible for vision. In the area of ​​the small head there are also two pairs of small antennas. The distant pair is larger in size and is covered with bristles. When they move slightly, the crustaceans make a peculiar movement in the form of a jump. Thanks to this feature, they began to be called water fleas.

In this video you will learn more about daphnia:

The body size of daphnia varies, as it depends on its species and ranges from 2 to 6 mm. Such tiny dimensions of the body do not allow one to clearly see its structure. What it looks like can only be seen under a microscope.

The body of the crustacean is oval in shape and covered on both sides with a special frame. It serves as protection for internal organs. The anterior antennae on the head are the organ of smell. Due to the antennas, daphnia moves along the water surface:

• repels;
• floats;
• makes leaps.

The crustacean has thoracic legs, which have the ability to pass single-celled bacteria and algae through them. This area contains gill sacs, with the help of which the water flea breathes. They are covered with many bristles that serve as a kind of filter. In 1 minute, the legs make up to half a thousand strokes.

The genus of these cladocera contains more than 150 species. Often found in our area:

• magna - the largest;
• Pulex - medium size;
• moina - small.

The stomach of any daphnia is always full of plant food, which is ideal for feeding aquarium fish. There's a lot in it useful substances, which are valuable in the nutrition of aquarium inhabitants.

Habitat

Daphnia are usually found in all standing bodies of water, from a pond to deep lake. These crustaceans are even found in Antarctica. The main condition for the habitat of daphnia is standing freshwater with a minimum amount of soil particles.

When daphnia enter groundwater, they filter the soil and gradually accumulate algae in their intestines, clogging it. These crustaceans do not like polluted water bodies, so they can be used to judge the cleanliness of a river, lake or pond.

They live for about 22 days

In reservoirs where daphnia live, most of their lives pass in the water column. Some species can live at the bottom, eating dead parts of plant food and the remains of invertebrate animals. They can also be found in other places - puddles, holes with water. Crustaceans react very sensitively to lighting, and when it is too bright, they go deeper. Large daphnia lives for 110−150 days. Life cycle other species are much smaller and can be up to 22 days.

Daphnia nutrition

Water fleas almost always live in natural bodies of water. Their main food is yeast and blue-green bacteria. A large concentration of unicellular vegetation is most often observed in “blooming” reservoirs, where there are not a huge number of fish.

Crustaceans constantly filter water saturated with unicellular microorganisms. They carry out such movements with the help of their thoracic legs. The filtered food enters the food chute in abdominal cavity and only then - into the esophagus. Upper lips with salivary glands and the secretion glues food particles into a lump.

Adults with an average concentration of food in a reservoir are able to filter food at a rate of 1-10 ml/t in 24 hours. Daily consumption will depend on the body weight of the crustacean. For example, in an adult magna it reaches 600% of its weight.

In cold weather, crustaceans can hibernate. However, most species with food available stay near the bottom, eating dead plant food and the remains of invertebrates, which is what daphnia feed on in the warm season. Their stomach is always full plant foods, therefore crustaceans are considered the best food for aquarium representatives. They are given in dry form, and they are also added to the fish in a container. The intestines begin to become more active thanks to this diet, since fish cannot fully move in a small volume of water.

Reproduction of individuals

Daphnia are distinguished by the peculiarity of breeding offspring without fertilization. Females of this species have a brood chamber. It is protected by the edge of the shell and is located on the back. Under favorable conditions, an adult can lay 50 to 100 unfertilized eggs. They develop in the cavity, and only females, and leave it independently. In females, molting begins after this.

After a few days, the reproduction process begins to repeat. Adult individuals join this cycle, so everything happens very quickly. One female can give birth to offspring up to 25 times over the entire period of her life. Because of this in summer time You can observe in reservoirs where daphnia live, the reddish color of the water. It is simply teeming with a huge amount of plankton.

With the onset of autumn, males join the breeding process. After fertilization, the shell on the eggs becomes denser. Future offspring are able to withstand frosts, as well as drying out water bodies, and spread with dust. When spring arrives, the breeding cycle begins to repeat itself again, as females emerge. New population of individuals in different time years may differ in body shape.

Conditions for breeding

Many people breed daphnia at home, which is quite simple. However, this process must be given due attention. The color of the water in the container plays a big role. It should be greenish or light brown.

It is impossible to allow other representatives of water bodies, for example, cyclops, to get into the container with daphnia. At home, the diet of crustaceans should consist of dry lettuce leaves or grapes. Baker's yeast is added to the diet. They are ground to a powder and then strained through cheesecloth. To get them at home, you need to take water with 50 crustaceans from a natural reservoir with prepared food and only then put them into the prepared vessel.

Large daphnia (lat. Daphnia magna) is a permanent inhabitant of any fresh water body.

It is sometimes called the freshwater flea or water flea and is familiar to many aquarium hobbyists as it is an excellent food for aquarium fish. It belongs to the Daphniidae family of the order Onychura.

Habitat

The ideal place for daphnia to settle are village ponds, which contain a lot of manure and oxygen-depleted water. Water fleas are resistant to changes in the amount of oxygen in water. This is explained by the fact that they are able to independently synthesize hemoglobin.

When oxygen decreases, hemoglobin in daphnia increases. They turn bright red and their numbers increase. With normal oxygen levels, crustaceans have a yellow-pink color.

Small crustaceans are permanent inhabitants of fresh water bodies, deep lakes, and small puddles. Many of them move along the bottom of the reservoir or leaves aquatic plants, and some scurry along the surface, periodically waving their antennae.

Small puddles and roadside ditches are good habitats for the water flea. In them, the water temperature is close to atmospheric and enriched with oxygen. The drying up of small reservoirs threatens the death of all its inhabitants.

Reproduction

The reproduction of daphnia is accompanied by a process of heterogony. In case of favorable conditions in the form of rainfall and filling of all depressions with fresh water, only females emerge from the fertilized eggs. After a week, they reach sexual maturity and begin procreation.

Up to a hundred eggs are laid in the female's brood chamber. The higher the temperature environment, the faster they develop. Young daphnia are born in the brood chamber. After this, the mother moults and lays the next batch of eggs. After one week, a new generation of juveniles is ready to breed.

After two months, the water in the puddle is already infested with water fleas. Such overpopulation often leads to the death of large numbers of daphnia. Then the surviving females begin to lay eggs, from which individuals of different sexes emerge.

After mating, the female lays 2 eggs. Under their shell, cells appear that surround the eggs in a dense layer, and on top of these cells a chitinous shell is created, which causes the ephippium to appear in the brood chamber.

Eggs placed in such a capsule are equipped with a huge supply of nutrients and look larger than usual. They can remain for a long time in a dry reservoir or frozen in ice, while maintaining their viability.

Sticking to the paws of birds, clinging to the fur of animals, to frogs or water insects, they are easily transferred from one body of water to another. Under favorable conditions, a new generation of females emerges from them, giving birth to a new population of water fleas.

Daphnia are excellent food for freshwater fish and other creatures that live near water. They reproduce with amazing speed. If all of its offspring survived, then in just one season it would reach 30 million individuals.

Behavior

Large daphnia populate water bodies in huge quantities, briskly scurrying around in the water column. They move with short nets, simultaneously flapping their antennae. For their spasmodic way of moving in water, they received the name water fleas.

Daphnia are active all day long. At night they swim closer to the surface of the water, and during the day they sink to the very bottom. They have from 4 to 6 pairs of thoracic legs equipped with setae. Such a filtering apparatus is used to obtain food.

The main food of water fleas is protozoa, algae, detritus particles and bacteria. Daphnia do not use their eyesight when hunting. Their eyes can only distinguish between light and shadow. During the movement of the legs, food enters the filter chamber along with the flow of water.

Morphology

The pectoral lobes of the pectoral legs are transformed into gills. Small claws are designed for cleaning the shell, and the back of the body is curved towards the abdomen. The transparent body of daphnia allows you to see it under a microscope internal organs- esophagus, circulatory system, blood circulation and brood chamber.

The size of the female is about 6 mm, and the male is up to 2 mm. The round head does not have a cervical interception. One compound eye was created by merging two lateral ones. The first pair of antennas is small. The rear antennae are more developed and are used as oars. The body is strongly flattened laterally. The double-leaf oval shell hides the entire body, leaving the head free.

The brood chamber is located on the back. The shell is running out tail spine.The lifespan of large daphnia does not exceed 19 days.

.

Daphnia from a home pond.

O. Tokarev, Zhukovsky, Moscow region.

Cladocera daphnia are used quite widely in aquarium practice. This is one of the most universal foods, suitable for both fry and adult fish of any species.
In nature daphnia live in ponds and large puddles where they feed various bacteria and phytoplankton. However, such reservoirs are often polluted industrial waste or they contain fish. Both can lead to diseases of aquarium inhabitants.
Daphnia may pose a danger to aquarists themselves. In spring and early summer, the diet of crustaceans often includes pollen. flowering plants, carried by the wind into bodies of water. Daphnia caught at this time and dried for future use when feeding fish can cause a painful reaction in people suffering from pollen allergies. This fact, in particular, can explain the often-found opinion that an aquarium is harmful to health. In fact, the reason is pollen, with which crustaceans are literally “stuffed” during the period of mass flowering of grasses.

A way out of these difficulties can be found in cultivating daphnia at home. To successfully breed crustaceans, the following is necessary. First, you need to create a complete bacterial
a crop that should be available for cultivation and well digestible Daphnia and have nutritional value. Secondly, it is necessary to provide a good oxygen regime for the crustaceans. Thirdly, you need water that is no worse in quality than for fish. You should not take water from the aquarium. By own experience I know that this can lead to the proliferation of ciliates, which will compete with crustaceans both in nutrition and in oxygen consumption. It is better to use well-settled tap water.
The most accessible and acceptable food for daphnia is baker's yeast. But they must be used carefully, since when applied in excess they cause severe turbidity in the water and the rapid death of crustaceans from lack of oxygen. A piece of fresh yeast the size of a match head should be dissolved in a teaspoon of water, but not poured in immediately, but in portions, while controlling the turbidity of the water. One-third of a teaspoon is enough for a five-liter jar.

Good food, according to German biologists N. and W. Horn, are green algae of the Scendesmus family, including green euglena (“Aquarien Terrarien” No. 8. 1976). These algae often appear in a newly equipped, “young” aquarium,
causing a lot of trouble for novice amateurs. I think with no less success daphnia would consume chlorella, the nutritional value of which is well known.
This “menu” of crustaceans, of course, does not end there. Carrot, beet, and cabbage juices added in small doses (less than a teaspoon per 5 liters) will not only diversify the diet of crustaceans, but also serve as a vitamin supplement to the feed. A good effect is achieved by adding small amounts of blood fluid formed after thawing frozen meat, as well as adding ammonium nitrate (and also a little). But adding milk or hay infusion, according to my data, does not contribute to the rapid reproduction of crustaceans.
The increase in daphnia biomass depends not only on the quality and quantity of food, but also on the type of crustaceans, water temperature and oxygen content in it. In my opinion, the optimal temperature is 22-24°C. The oxygen content is determined by the density of crustaceans, temperature and the degree of saturation of water with bacteria. It is necessary to control the turbidity of the water, not allowing it to increase excessively. Water should under no circumstances have any odor. Low aeration may contribute to success.

But strong bubbling water is poorly tolerated by crustaceans. They also do not like bright sunlight.
It is best to breed daphnia in shallow containers with sufficient surface area (1200-1500 square centimeters). It is advisable that the containers be round rather than rectangular, since zones are formed in the corners where water does not mix well. Regular water changes are necessary: ​​1-2 times a week, a third to a quarter of the volume.
The signal to add feed to the crop is the clearing of the water. The rate of application of green algae, according to N. and W. Noga, is 300 milliliters per five-liter jar. According to the same data, the optimal density of Daphnia magna is 300 crustaceans per liter (meaning non-adult specimens).
Under favorable conditions, female daphnia lay eggs without the participation of males. The largest ones should be planted and used as producers.
Unlike artemia nauplii, juvenile daphnia are softer and therefore more readily eaten by fry. Of course, at home it is impossible to provide such food to all aquarium fish (if, moreover, they are adult breeders). From three five-liter jars I had enough crustaceans to feed one and a half to two hundred fry, mainly characin fish, which spawn better in winter.

For home culture, it is best to use daphnia caught in the summer, as they can more easily tolerate high room temperatures. I was able to successfully cultivate D. magna, D. pulex, as well as their relatives - moins, often called livebearers or "spiders". The easiest one, of course, is to deal with D. magna. Adult specimens that reach 5 millimeters produce a lot of offspring. However, these daphnia are more sensitive to the amount of oxygen contained in water and do not tolerate temperatures above 24-25°C. But they can withstand its reduction to 10°C, which makes it possible to increase the density of the crop.
As you know, daphnia are an excellent biological filter: by passing water through themselves, they destroy bacteria. F. Polkanov drew attention to this property of crustaceans (“Fish farming and fishing” No. 5, 1975). In particular, he recommended that aquarists use moin to clean the culture of ciliates from bacteria before introducing it into the aquarium for feeding to larvae, as well as to purify the water in the spawning grounds of those fish whose larvae are sensitive to bacteria. Unfortunately, the last recommendation does not always give the desired effect. It happens that fish larvae, especially characins, die faster than the crustaceans can cope with the bacteria. And the temperature in the spawning tank is too high for them - you can’t put many crustaceans there. But they perfectly purify the water in a newly equipped aquarium, prevent it from “blooming” and thereby contribute to the establishment of biological balance.
At first glance, it may seem that cultivating daphnia is quite complicated and impractical. Of course, like everyone feed object, bred at home, they require certain attention: they need to be fed and the water regularly replaced. In addition, you have to sacrifice containers - fish tanks or small aquariums. But the opportunity to have all year round environmentally friendly live food, the quality of which you can set yourself, of course, pays for all the inconveniences listed above.