Ammonia burns are the most common reason that goldfish turn black. High ammonia content in fish tanks causes irritation and trauma to the goldfish's fins. Ammonia burns are white in color and turn black as the goldfish heals.Know More
Additional reasons for a goldfish to turn black include ingestion of colored fish flakes and genetics. Many goldfish possess a random mix of color genes, which in turn can lead to color variations.
High ammonia levels in a fish tank are easily remedied with a 25 to 50 percent water change. Ammonia levels tend to fluctuate when there is undigested food or fish droppings in the water as these items emit excess ammonia while decomposing.Learn More
The most common reasons for goldfish to turn black are genetics and ingestion of colored food. Dark environments also cause goldfish to produce additional melanin, which results in a change in pigment. Disease is uncommon, but in certain cases, diseased goldfish turn black.Full Answer >
There are breeds of goldfish that are characterized by bulging eyes. However, for other breeds, if the eyes on a goldfish are protruding, it may be that the fish has an infection, is physically injured or has a metabolic disorder or that the eyes are responding to poor water conditions.Full Answer >
Although there is little proof, rare cases have indicated the possibility of cannibalism in goldfish. The National reported an incident in which goldfish ate other fish after an earthquake, leaving them of food for an extended period of time.Full Answer >
Swim bladder disorder is the most common reason for a betta fish to float on its side. There are numerous causes of swim bladder disorder, including disease, physical trauma, parasites, environmental factors and constipation.Full Answer >