Figure 1 Tap water is often used for goldfish culture.
1, how to choose water source and ensure water quality
In general, fish friends in cities will use tap water or deep well water, while fish friends in rural areas will use river water, lake water, well water, spring water and snow water. These water sources can be divided into surface water, groundwater and tap water after disinfection. Rainwater can't be used as the water source for goldfish breeding, because it contains more impurities and low oxygen content, and air pollution makes it acidic. Urban rivers, sewer water and sewer water are absolutely forbidden to be used as water sources for goldfish breeding, because there are many harmful factors.
Tap water is widely used by people who love fish. Most tap water in cities is made of surface water after precipitation and disinfection. Because of the large contact area between surface water and air, more dissolved oxygen in water, less impurities after precipitation treatment, less pathogens after disinfection treatment and abundant water sources, it is generally considered to be an ideal goldfish feeding water. However, because the tap water is disinfected by bleaching powder, different amounts of chlorine gas often remain in the water, which is toxic to the body surface and gill tissue of goldfish and often leads to the death of goldfish. Therefore, it must be properly treated before use, and it can be used as feeding water for goldfish, usually exposed to strong sunlight 12 hours or more. If it is urgent to use tap water to change water, sodium thiosulfate can be used to neutralize chlorine in tap water. Generally, one gram of sodium thiosulfate is put into every cubic meter of water to neutralize the chlorine in the water before use. But generally speaking, we usually raise goldfish by sun exposure, or use special filtering equipment to filter for more than ten hours, and only use sodium thiosulfate to neutralize water when it is urgently needed. This method should be used as little as possible, because if the dosage is not well controlled in summer and high temperature season, the water will be turbid and cannot be used.
Fig. 2 The rearing environment of goldfish is much more casual than that of marine fish.
2. How to choose fish feed
Goldfish is an omnivorous fish, which can not only adapt to the natural animal and plant feed, but also eat artificial feed. There are many kinds of feed for goldfish. It should be noted that the deteriorated fish feed must not be fed, otherwise it will directly affect the healthy growth and water quality of goldfish, and may even lead to hypoxia, illness and death of goldfish. Therefore, we should pay great attention to the quality of feed in the usual feeding process. It is best to store fish feed 20 cm away from the ground, because if the fish feed is too close to the ground, it may be moldy and deteriorated because the ground is wet. When feeding fish feed, we should also control the amount and feed it appropriately according to the size and appetite of goldfish. Similarly, the variety selection of fish feed also depends on the palatability of goldfish and the flow rate of water quality filtration system. Granular feed is widely used now. The advantage of granular feed is that goldfish floating on the water surface can be eaten without waste, and it is also convenient to clean up excess feed and keep the water clean.
Figure 3 Black Mary
3. How to prevent diseases
Common diseases of goldfish are as follows:
(1) White spot disease: This disease is a common disease of domestic ornamental fish, and its main symptom is that many white spots appear on the body surface, fins and gills of the sick fish. The pathogen is multi-seed melon bug, so it is also called melon disease. Fish are densely parasitized by a large number of small melon worms to form white spot vesicles, which can cover the whole body in severe cases. In the later stage, the body surface is covered with a white film, with increased mucus and dull body color. Sick fish are thin, floating on the water or in the corner of the cluster, and rarely move. Cucurbitaceae has obvious seasonality, and the water temperature of 15-20℃ is most suitable for the propagation of Cucurbitaceae. The water temperature can be raised to 30 degrees by using the method that the small melon worms are not resistant to high temperature. Promote the rapid maturation of spores produced on the surface of fish, accelerate their growth, and then choose mercurous nitrate, malachite green and formalin after they fall off the surface of fish.
Fig. 4 goldfish with white spot disease
(2) Water mold: The reason of this disease is that water mold invades from the wound of the fish, begins to parasitize on the epidermis, gradually penetrates into the muscle, absorbs the nutrition of the fish, multiplies in large numbers, and produces gray or blue-white hyphae (visible to the naked eye as cotton silk). Inflammation, congestion, necrosis and ulceration of the wound in the parasitic part; Sick fish often rub the affected area with cylinder wall, gravel or aquatic plants, and finally die of exhaustion. The disease can occur all year round, and it is most popular in early spring and late autumn. Young fish that are scratched and frostbitten are susceptible; Fish eggs that are not fertilized and have poor embryo vitality are also easy to parasitize. The key to prevention is to keep the water clean, the water temperature is appropriate, the fish are strong and do not cause trauma. The diseased fish can be soaked in salt water or potassium permanganate, furacilin and malachite green solution or applied locally for treatment.
(3) Baiyun disease: The main cause of this disease is the great change of water temperature, which leads to oral filariasis, trypanosoma and rotifer. Parasitic on fish, stimulating goldfish to secrete a lot of mucus, making the parasitic parts appear white turbid spots, which look like white clouds, and it is difficult to breathe when parasitic on fish gills. During the treatment, the fish tank can be filled with 500ml of water, then 1 ml of formalin is poured in, and the sick fish can be put into the medicated bath for 30 seconds every time and once every seven days, which can effectively cure.
Fig. 5 Typical symptoms of Baiyun disease