The optimal water depth for keeping goldfish should be adjusted according to the goldfish's breed, breeding stage, and rearing environment:
Water Depth Requirements for Different Goldfish Breeds:
- Top - viewing goldfish (such as butterfly - tail goldfish, pearl goldfish, etc.) prefer relatively low water levels, generally ranging from 10 to 35 centimeters.
- Side - viewing goldfish (such as ryukin goldfish, Thai lionhead goldfish, etc.) need higher water levels, usually varying from 30 to 80 centimeters.
Water Depth Requirements Based on the Breeding Stage:
- During the head - growth stage of goldfish (for breeds like lionhead, tiger - head, etc.), a shallower water level is beneficial for the growth of the head growth.
- For high - backed breeds (such as ryukin, Thai lionhead, etc.), during the formation stage of the dorsal line, a deeper water level needs to be maintained.
- Newly hatched fry, due to their small size and weak constitution, require the water level to be controlled at a relatively low level, around 10 centimeters.
The Impact of the Rearing Environment on Water Depth:
- When rearing goldfish outdoors, especially in traditional earthen ponds without a filtration system, the water level needs to be appropriately deepened both in summer and winter.
- The larger the water body, the deeper the rearing water depth can be. For example, ranchu goldfish can grow well in water deeper than 50 centimeters.
Commonly Used Water Levels for Domestic Goldfish:
- For adult and easy - to - keep goldfish (such as comet goldfish, lionhead, etc.), a deeper water level is not a problem. Instead, a water body of 50 centimeters or more is optimal.
- For adult fish of breeds like Chinese ranchu and longevity goldfish, a water level of 30 to 40 centimeters is more suitable.
- For adult fish of breeds such as pearl, bubble - eye, butterfly - tail, and Japanese ranchu, a water level of around 30 centimeters is sufficient.
In addition, the water depth can also be adjusted according to the behavior of goldfish. If goldfish are always swimming near the water surface, it may indicate that the water depth is too deep and needs to be appropriately reduced. If goldfish are swimming at the bottom, it may mean that the water depth is too shallow and needs to be increased.
In conclusion, there is no fixed standard for the water depth of keeping goldfish. Instead, it needs to be comprehensively adjusted according to the goldfish's breed, breeding stage, rearing environment, and behavior.