1. Reason: Black spots on the scales of Yinlong fish may be caused by infected bacteria, and they have strict requirements on water quality. If the water in which they live has more harmful substances or bacteria, they are easily infected. After the silver arowana is infected with bacteria, it will have dull expression, reduced activity and loss of appetite in the early stage. Only when bacterial infection is serious, sporadic white spots will appear on scales.

2. Solution: The breeder needs to isolate the silver arowana immediately to prevent them from infecting other fish with bacteria. When moving to a new fish tank, the breeder needs to keep the water clean, so as to avoid the growth of bacteria. Then they need to be given a medicated bath with 0.5 ppm guppy stone green solution and 25ppm formaldehyde solution, once a day for 7 consecutive days, and the black spots will become shallow or disappear.

1. Reason: Black spots on Arowana may also be color spots, which are not diseases. They are the same as human freckles, but they will affect beauty and will not endanger health. The main causes of color spots in Arowana are pigmentation and poor water quality.

2. Solution: The breeder can carefully observe their daily activities. If their eating and activities are not affected, the breeder does not need to deliberately treat them.