How to Differentiate Goldfish Sexes
- 1). Inspect the fish's vent area, located under the tail fin. When fish are ready to spawn, the male's vent becomes longer and concave, while the female's fin protrudes like a small bubble.
- 2). Observe the fish's overall body. Females are larger and rounder than males, while males are more narrow and compact.
- 3). Observe the behavior of multiple fish in a tank. During spawning time, a male will bump the female's vent with his nose.
- 4). Inspect the fish's gill covers and pectoral fin. Males develop spots, called breeding stars, on these areas. These spots are absent on females.
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