The body of a goldfish is like a thermostat, which can adjust its body temperature to the same level as the environmental temperature at any time. When the water temperature rises or drops, this change is quickly spread throughout the body through the microvessels in the fish’s skin and the blood vessels in its gills, causing the fish’s body temperature to change accordingly. However, the adaptability of any fish species to water temperature is limited. Different fish species have different adaptation ranges. According to the adaptation range to water temperature, all fish species can be classified as follows:
Tropical fish: They have a certain limit to the range of temperature changes they can tolerate. When the temperature change is around 10°C, tropical fish will die one after another due to their inability to adapt to the environment.
Cold-water fish: Generally, they cannot survive in water bodies with a temperature above 20°C.
Eurythermal fish: Goldfish have a relatively wide adaptation range to water temperature and can survive in water temperatures ranging from 0°C to 38°C, belonging to this category. However, goldfish have the weakness of not being able to tolerate sudden changes in water temperature. For example, if the water temperature suddenly rises or drops by more than 5°C, goldfish will get sick or even die immediately. Under the same magnitude of water temperature change, young fish are more sensitive to sudden changes in water temperature than adult fish. In this regard, sudden changes in water temperature pose the greatest threat to the healthy growth of goldfish. Especially when adding new water to the goldfish tank, it is crucial to ensure that the temperature of the new water is basically the same as that of the old water.
When the water temperature approaches 0°C, goldfish are in a “semi-rigid” state and basically do not move. When the water temperature is between 6°C and 8°C, goldfish start to feed. When the water temperature is between 8°C and 10°C, the feeding activities of goldfish are obvious. When the water temperature is between 10°C and 15°C, goldfish can grow slowly. When the water temperature is between 18°C and 28°C, goldfish can grow normally. When the water temperature is between 28°C and 30°C, the breathing of goldfish speeds up, but they can still grow. When the water temperature is between 30°C and 32°C, goldfish start to show some unusual behaviors and often gather near the water surface, and they cannot grow normally. When the water temperature exceeds 34°C, goldfish are simply “suffering”, and not all goldfish can survive for a long time. When the water temperature is around 37°C, it is a “dangerous” water temperature, and the temperature should be lowered immediately.
Since the water bodies for breeding are relatively small and there are many different species involved, the temperature management of ornamental fish is very complicated. For example, fish native to temperate regions can live well in water temperatures above 22°C in summer and can normally move in water around 4°C in winter. However, for the vast majority of tropical fish, the temperature needs to be maintained within a relatively narrow range, that is, between 20°C and 30°C. If the temperature is higher or lower than this range, they will experience various discomforts. Especially when the temperature is lower than 15°C, many tropical fish will die due to the low temperature. Generally, the water temperature for breeding goldfish and koi should not be lower than 5°C, and the water temperature for breeding tropical fish and marine fish should not be lower than 20°C. The water temperature for the reproduction of ornamental fish should be maintained between 18°C and 25°C. The specific temperature varies depending on different fish species. When breeding fish, attention should be paid to the water temperature requirements of different fish species to ensure their normal growth.
In addition, the reproduction of each species of ornamental fish should be carried out at the optimal water temperature permitted by science. If it exceeds the suitable range, their reproduction is difficult to succeed.
Through breeding, we can find that the view that the higher the water temperature is within the suitable temperature range for the growth of ornamental fish, the better they will grow is not comprehensive. This is because as the water temperature rises, the dissolved oxygen content in the water will decrease, which will inevitably affect the growth of ornamental fish. In addition, when the water temperature rises from 24°C to 30°C, the number of bacteria in the water will increase rapidly. It goes without saying that the probability of ornamental fish getting sick will increase significantly at this time.
Whether breeding or reproducing ornamental fish, it is essential to control the water temperature artificially. When breeding, the daily temperature difference of the water temperature should preferably not exceed 6°C. When reproducing, the daily temperature difference of the water temperature generally should not exceed 4°C.
The ornamental fish tank indoors should be placed in a place where the water temperature can be kept constant. Within the specified range, the size of the fish tank should preferably be larger. Because the larger the volume of the fish tank, the more water it can hold. In a unit of time, the change in the water temperature inside the fish tank will be smaller, and the water temperature will not rise or fall significantly in a short period due to sudden changes in the air temperature.
Before preparing to pour in fresh water, the new water should be placed near the fish tank for a period of time. It should be poured in only after the temperature of the new water is the same as that of the water in the fish tank to prevent a sudden change in the water temperature inside the fish tank.
In the hot season, if the air temperature is too high, you can sprinkle water on the ground near the fish tank, which will lower the air temperature around the fish tank. In the cold season, the fish tank should be placed in a warm and wind-sheltered place. When the air temperature is too low, the fish tank needs to be heated. When heating, it should be noted that the fish tank should be placed in a higher place. Because when the air is heated, it will become lighter and rise, making the air temperature in the upper part of the room higher than that in the lower part. Placing the fish tank in a higher place will result in a better heating effect.
