How to Tell the Gender of Goldfish

Goldfish have been bred for many centuries. Through selective breeding, a variety of colorful and unusual goldfish have resulted. If you're a goldfish owner and curious about how to tell the gender of your goldfish, you must wait until your fish reaches sexual maturity. This can take about an average of one year, indicates Steve Hopkins of Rain Gardens Ornamentals. However, once you've mastered the technique of sexing your goldfish, you can pair your favorites, to improve the quality of future generations.

Things You'll Need

Aquarium fish net

Instructions

- 1
  Identify breeding tubercules, which male fish have on their gill plates and pectoral fins, according to Aquarium Industries, an Australian importer of aquarium fish. Breeding tubercules appear as pimple-like white spots, and can be mistaken for ich, a dermatitis disease, caused by the protozoan Ichthyophthirius.
- 2
  Look at the body of your goldfish. Females tend to have broader bodies, which become larger and rounder prior to breeding. A female will look lopsided when it begins to carry eggs. Females can also have smaller pectoral fins, which are located beneath the gills.
- 3
  Observe the shape of your goldfish's vent. The vent is the external opening that leads to the digestive, reproductive and urinary tracts of your fish. When a female is ready to breed, its vent will bulge outward, notes Steve Hopkins. A male's vent has a triangular shape.
- 4
  Use an aquarium fish net to gently scoop your goldfish out of its aquarium. Inspect the goldfish's vent. Gently press the fish's abdomen with your forefinger and thumb. If milt, a white reproductive fluid, expels from the vent, you have a male goldfish. If your fish is female, it's possible that eggs will be expressed
- 5
  Watch your fish for spawning characteristics. Males will flock to a female when interested in mating. Females will disregard each other. Males may also nip at a female's fin in an attempt to get it to release eggs.