The sex of a black moor goldfish is not identifiable until after it is one year old. During the breeding months from April to August, a male goldfish will sport white bumps, called breeding tubercles, on its gill coverin... More »

The standard method to identify the gender of a baby is an ultrasound between weeks 16 and 20 of pregnancy, according to Baby Center. Though health assessment is the primary motive of a mid-pregnancy ultrasound, the baby... More »

Most methods of determining the gender of kittens use visual clues in sexing the kittens. Determining the gender can be confusing for inexperienced individuals. More » Pets & Animals Pets Cats

According to, determining the gender of a goldfish can be difficult, as the fish are weakly dimorphic. However, depending on when the fish are checked, it can be possible to determine their gender based o... More »

The most common cause of black spots on goldfish are trauma and irritation due to high ammonia levels in the water. High ammonia actually burns the scales, resulting in white patches. The black spots appear as the scales... More »

Goldfish often turn black due to genetics, according to A goldfish can change color several times over the course of its life. When a goldfish begins turning black, it is often not a serious issue and is... 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 uncommo... More »