The main reasons for goldfish turning black include water quality problems, disease factors, improper feeding, and physiological changes.
Water Quality Problems: Not changing the water for a long time will lead to water quality deterioration and the growth of bacteria. The water may contain excessive harmful substances such as ammonia and nitrates, which can cause goldfish to turn black. It is recommended to change the water in the fish tank regularly to keep the water quality clean. Change the water at least once a week, and each time replace about one-third of the water volume.
Disease Factors: Goldfish may suffer from black spot disease or pinecone disease, and these diseases can cause goldfish to turn black. Medications such as methylene blue and potassium permanganate solution can be used for treatment, or special drugs like Kirofen No. 4 Yukangbao can be used to control inflammation and inhibit harmful bacteria.
Improper Feeding: Overfeeding or poor-quality feed will cause indigestion in goldfish, which in turn affects their body color. Reasonably control the amount of feeding, avoid overfeeding, and ensure the quality of the feed.
Physiological Changes: During pregnancy, the spawning area of goldfish may gradually turn black, which is a normal physiological phenomenon.
Treatment Methods:
Improve Water Quality: Regular water change is the key to keep the water quality clean. New water should be left in the sun for one or two days to remove chlorine before adding it to the fish tank.
Medication Treatment: For black spot disease, methylene blue or potassium permanganate solution can be used for treatment, and special drugs can also be used as adjuvant treatment.
Isolate Sick Fish: During the treatment period, isolate the sick fish to prevent infection, and reduce the amount of feeding to avoid indigestion.
Get Some Sunlight Appropriately: Appropriate exposure to sunlight is helpful for the recovery of goldfish.
Preventive Measures:
Keep Water Quality Clean: Change the water regularly and use a filter to maintain good water quality.
Feed Reasonably: Control the amount of feeding and avoid overfeeding.
Observe the Condition: Regularly check the body color, scales, and swimming state of goldfish, and take timely measures when abnormalities are found.