Gammarus fish food is a small barnacle crustacean. The Latin name of this species is Gammarus pulex, it belongs to the order Amphipoda (bokoplavy), which has about 4,500 species. More often in common usage, outside the aquarium theme is used the word mormysh, which is a collective, it denotes just those 4,500 species of the Amphipoda. Mormysh is used by fishermen as bait for hooking fish. For feeding aquarium fish, aquarists more often use it is Gammarus pulex. Which was described by Linnaeus as early as 1758. The same species is used to feed valuable commercial fish species in fish farms.
Synonyms: muzzleloader, sea flea, bokoplava crustacean, Rivulogammarus, Sinogammarus.
Habitat: The mormyr is widespread. It lives in fresh or brackish waters. Gammarus is a freshwater species.
Gammarus fish food Description
This bocoplave crayfish has a curved body consisting of 14 segments covered with a hard shell. The length of the body is about 1 centimeter. Mormysh – a collective name for all species, among which there are quite large. Some of them can reach a length of up to 3 centimeters. The described species has 14 pairs of limbs. The first two pairs are represented by antennae – a kind of tactile apparatus. These are grasping organs for grabbing, as well as holding food.
They are also used by the male to cling to the female’s back during breeding. The first three abdominal pairs of legs are swimming, the last three help the animal to make rather rapid jumps. The hind legs are covered with a large number of bristles, they play the role of an effective rudder. Under the thin, but strong enough plates of the thoracic limbs are delicate gills. These legs constantly make oscillatory movements. With their oscillatory movements, they provide a constant flow of water to the respiratory organs of the animal.
Gammarus lives for about 1 year. Withstands temperature fluctuations from 0 to 26 degrees Celsius. Prefers cool, shaded from direct sunlight, oxygen-rich waters.
The colour of the gammarus depends on its food
The color of the chitinous shell can vary from brown-green to light yellow. This is determined by the food base of a given population. The green color of the shell becomes green when the animal feeds on plant food, and it is colored by plant pigments that plants contain.
Gammarus Baikal feeding on small plankton can have brown, colorless, as well as red coloration. It feeds and grows constantly. As it grows, there are molts, during which the animal gets rid of the old chitin shell, which has become cramped. Molts occur at intervals of 7 days in summer and 16 – 17 days in winter. After the seventh molt, the female has peculiar growths on her abdominal limbs that form the so-called brood chamber. It is a kind of hollow tube. It reaches sexual maturity after the tenth molt. The mormysh may reproduce from one to several times a year.
This is determined by the habitat. The colder it is, the less frequent the breeding. During spawning, the male clings to the female’s shell. He can ride like this for up to 7 days, waiting for the female to molt again. When her molt begins, the male will help her get rid of her old chitinous clothing. He will then lubricate the walls of her brood pouch with his seed using his abdominal legs. Copulation lasts up to a few seconds. After that, the male leaves his mate, and she lays up to thirty large dark eggs in the brood pouch. In warm weather, their development lasts from two to three weeks. Young gammarus emerge from the brood pouch fully formed.
Gammarus fish food How to get it?
- A bundle of straw or hay, which is placed at the bottom of the pond. Having found such a treat, mormyshka very quickly climbs between the straws and blades of grass filling all the cracks. Now it remains only to take your bait out of the water and choose your prey from it.
- Sometimes the bokoplavy can cling to a sack tied to a long stick with which the sack is slowly pulled over the bottom. Only a sack made of cloth woven from hemp is suitable for this purpose. After a few minutes, the bag can be removed from the water and the animals collected by hand.
- If the water body where you are going to catch Gammarus pulex contains a lot of algae you can try to catch it with a net made of a capron stocking.
Gammarus fish food How to store?
Your catch can be stored live, dried, frozen.
In order to keep the bokoplava alive, it is necessary to place it in a container with water from the reservoir from which it was caught. The bottom of the container should be covered with soil from the same reservoir. If possible, the tank should be placed where it is cool and dark. It is necessary to establish constant aeration, as gammarus is very sensitive to the lack of dissolved oxygen. Every day you should change 1/3 of the water with fresh water (you can tap water).
Approximately in this way create conditions for more or less continuous preservation of Rivulogammarus alive. Abroad there are even farms for breeding Gammarus pulex. Certainly, the description given here is far from complete. This topic is worthy of a separate article. Although, of course, no valuable instructions will not replace personal experience, which you will have to acquire, in accordance with the population of bokoplav crustacean, which will get to you.
Your catch can be wrapped in a damp cloth. Then you should also put the bag in a cool, dark place. If the bag is not too large, the bottom shelf of the refrigerator will do. Every day, the cloth and its contents should be washed. You can store mormysh in this way for about a week.
If the catch is large, it is better to dry it. In doing so, try to adhere to the following mandatory rules:
Only fresh, not beginning to spoil Gammarus pulex can be dried.
Before drying, it is sometimes recommended that the raw material be steeped in hot water. Without going into details about the advisability of this procedure, I will only note that it should be really hot water, not boiling water. Any heat treatment leads to the destruction of vitamins, with which dried food is already poor, which further deteriorates the quality of the final product.
Drying should be done in fresh air, where there is air circulation. Shellfish should be spread in a thin layer on gauze stretched on a rectangular frame so that the air circulates from below. The frame should be placed in the shade, under some kind of canopy, protecting it from direct sunlight. It is not necessary to resort to “express drying” with the help of an oven. It seems to me that fish do not like fried food.
Dried feed should preferably be used within three months if stored in a leaky container with access to air. With longer use, the nutritional value of such food decreases dramatically. Therefore, do not stockpile these raw materials for ten years in advance.
Gammarus can be frozen. In this case, the same recommendations should be followed as when preparing the raw material for drying. What can be added is the recommendation to divide the entire stock into small portions that can be eaten either at one time or several times during one week. Now you can freeze these portions at a temperature of minus 18 -25 degrees Celsius. Most modern household freezers can handle this task. According to some reports, the frozen bokoplava crayfish can retain its nutritional properties for up to two years.
Gammarus fish food Where to buy?
You can buy live Gammarus pulex at the market or in stores selling pet products. If you want to buy a live Gammarus pulex, it is most likely possible only at the nearest market where they sell our little brothers and food for them.
Dry and frozen food is better to take in specialized stores or from an acquaintance whom you know for many years and the quality of his goods does not cause you doubts.
The most famous suppliers of dry food for aquarium fish on the Russian market today are Tetra, Sera, Tropical, Nutrafin (Hagen), Otto, Wardley, Dajana Pet, Munster Aquarium, and others. When buying these products, pay attention to the date of manufacture and expiration date. It should also be remembered that after breaking the seal of the package, its contents must be used within three months.
Nota Bene! Allergies
It should be remembered that the chitinous shells of all crustaceans and insects contain strong allergens. Children should not be given boiled crayfish, crabs, shrimp. Due to not established mechanisms of their immune system, strong food allergic reactions to substances that contain chitin shells may occur.
Gammarus pulex of course no one is going to give children as food, but when drying this crustacean its chitin shells become very brittle. Therefore, when feeding fish, tiny particles of dried chitin shells can be formed, which can be suspended in the air for a long time. Now the particles containing these allergens will not come into contact with the human body through the digestive tract, but through the respiratory tract.
For the same reason, it is strongly recommended that you do not cover your floors with the trendy carpets. The gaps between the carpet pile are ideal breeding grounds for dust mites. These “pets” can be seen only with a microscope, but they are also covered with a chitinous shell, which after the death of the animal is rubbed by our feet to the state of the smallest powder. Rising into the air it, getting into the respiratory tract, can also cause allergic reactions. Therefore, if after contact with dry food you notice skin itching, redness of the skin, lacrimation or breathing difficulties, you should urgently seek medical attention.
Depriving your child of an aquarium or yourself without your favorite hobby is not worth it. Allergies are not for the aquarium!
Henceforth, the use of dry feed should be discouraged and live or frozen feed should be used.
Gammarus fish food Nutritional value
Gammarus feed contains a dry matter of 12.8%. Of this, the share of protein is 56.2%, fats 5.8%, carbohydrates 3.2% . It is also rich in carotene, a provitamin of vitamin A. It is to this component attributed the ability to make the coloration of fish and birds especially bright. Quite a decent meal.
But it is not recommended to give only gammarus. However, as well as all other types of food should be alternated with each other. For the most general case it is enough to give gammarus food to your pets 1-2 times a week.
The bokoplava crayfish is relatively large. Therefore, it can be given to medium and large fish. For small fish or fry, the mormysh can be crushed. The dry one can just be lightly rubbed between the fingers. Live or frozen Gammarus pulex can be pre-steamed for a few minutes with hot water to soften the chitinous shells and then cut into pieces of suitable size.
Rivulogammarus is a valuable, nutritious food for your fish. If you follow the simple recommendations given in this article, all the unpleasant moments that may arise when using Rivulogammarus will be minimized. I hope the article was interesting and useful to you in some way.