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How Do You Determine the Gender of a Black Moor Goldfish?

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Sexing a goldfish is a difficult task due to the fact that males and females look nearly identical unless they are in a breeding state. To correctly determine the gender of your black moor goldfish, you will first need to wait until he or she is at least 1 year old. While males are normally smaller than their female counterparts, the only sure indicator of gender is the visible difference between the two sexes during spawning season.

Step 1

Wait for spawning season to occur. Goldfish spawn once each month between April and August, preferring to have their young during warmer summer months.

Step 2

Locate your goldfish’s gill covers and pectoral fins. Gill covers are directly over the gills and the pectoral fins are the two bottom fins near the front of the body.

Step 3

Examine the gill covers and pectoral fins for small white bumps. These bumps are known as “breeding tubercles,” and only appear on male goldfish. If you do not see any on your fish during breeding season, the fish is likely female.