Detailed Guide to Distinguishing Male and Female Guppies
I. Body Size Differences
Adult Size
Female Guppies: Can reach 5–7 cm in length.
Male Guppies: Typically 3–5 cm in length.
Body Shape
Females: Round, swollen abdomen; sturdy overall body.
Males: Slender, streamlined body.
II. Caudal Fin (Tail Fin) Characteristics
Fin Shape
Females: Fan-shaped caudal fin; relatively small.
Males: Large, ornate caudal fins with varied shapes (e.g., triangular, round, swordtail).
Fin Color
Females: Pale caudal fins, often transparent or solid-colored.
Males: Brightly colored caudal fins, usually with metallic sheen and complex patterns.
III. Anal Fin Differences
Fin Shape
Females: Fan-shaped anal fin with rounded edges.
Males: Anal fin modified into a gonopodium (mating organ) — thin and rod-like.
Fin Function
Males: The gonopodium is used to transfer sperm during mating.
Females: The anal fin supports the body during egg-laying.
IV. Body Coloration
Overall Color
Females: Plain coloration, mostly silvery-gray or pale yellow.
Males: Vivid coloration, often with metallic patterns in red, blue, yellow, etc.
Color Development Timing
Males: Start showing bright colors at around 2 months of age.
Females: Minimal changes in body color throughout growth.
V. Behavioral Traits
Swimming Style
Males: Swim with caudal fins spread wide (to display for mating).
Females: Calmer swimming; smaller caudal fin movements.
Mating Behavior
Males: Chase females and display their fins to attract mates.
Females: Choose to mate with males that have brighter coloration.
VI. Sexual Maturity Timing
Males: Reach sexual maturity at approximately 2–3 months of age.
Females: Reach sexual maturity at approximately 3–4 months of age.
(Note: These differences are not obvious in fry (within 1 month of age) and gradually become visible as they grow. Some artificially bred guppy varieties may have unique traits that differ from the above.)