The reasons why parrot fish tails turn black:

1. Being frightened. It may be caused by being frightened, or it may be caused by competing for territory with other fish species.

2. Water quality and temperature issues. Although parrot fish do not have high requirements for water temperature, they are very sensitive to temperature differences. If the temperature difference is higher than 2°C when we change the water, they will have a stress reaction and their tails will turn black. And poor water quality in fish tanks can also cause the color of their tails to turn black or their bodies to turn lighter.

3. Melasma. The blackening of the parrot fish's tail may also be caused by black spot disease, which is caused by bacterial infection in the water, because the bacteria will parasitize the eggs and body wounds of the parrot fish.

Treatment methods for parrot fish tail turning black:

1. Create a quiet environment. If the parrot fish is frightened, the owner can move the fish tank to a relatively quiet and dark place in the room and wait for the parrot fish to recover on its own. If there is no way to move the fish tank, then cover the fish tank with a thick layer of cloth to make the parrot fish feel safe.

2. Maintain water quality and temperature. If it is caused by water quality and temperature, the owner will have to change the water in the fish tank in about a week, with one-third of the water replaced each time. At the same time, the daily water temperature should be kept between 28 and 28 degrees Celsius as much as possible. between.

3. Drug treatment. If parrot fish suffers from black spot disease, owners can treat it through salt water immersion and antibiotics. Use 2-3% salt water to soak once a day for 5-10 minutes each time for several days. The dark spots will fade or disappear.