Body Shape:
- Male goldfish tend to have a slender body shape, while females are generally rounder and have a more robust belly, especially during breeding season.
Anal Vent:
- The anal vent is located on the underside of the fish, just behind the belly. In male goldfish, the anal vent is usually smooth and slightly raised, often referred to as a "pointed" or "V-shaped" vent. In females, the anal vent is typically rounder, larger, and may appear slightly swollen or "U-shaped" during the breeding season.
Breeding Stars:
- Breeding stars, or "nuptial tubercles," are small white bumps that appear on the head and gill covers of male goldfish during the breeding season. These bumps are most visible during spawning and help the male grip the female during the mating process.
Behavior:
- During the breeding season, male goldfish may chase and nudge female goldfish in an attempt to initiate spawning. They may also display territorial behavior by chasing away other males from their chosen breeding area. Females, on the other hand, are generally less active during this period and may appear ready to spawn when they have a swollen belly.
It is important to keep in mind that these are general characteristics and may vary slightly among different goldfish varieties. If you are unsure about the gender of your goldfish, you can consult with a knowledgeable aquarist or veterinarian for a more accurate determination.