The Gravid Spot
The gravid spot is the dark patch near the rear of the female belly, behind the anal fin. In early pregnancy it is small and gray. As pregnancy progresses (4-6 weeks total), it darkens to deep gray or black and grows larger.
Just before birth, you can sometimes see fry eyes inside the gravid spot — tiny dark dots through translucent skin.
Body Shape Changes
A non-pregnant female has a smooth, gently curved belly. A pregnant female develops a "boxy" or square belly profile when viewed from the side. From above, she looks wider.
Late pregnancy: belly is large, almost dragging, and the female swims slower. She may seek hiding spots in plants or decor.
- ✦First-time mothers have smaller broods (5-15 fry).
- ✦Experienced mothers can deliver 50-100 fry per brood.
Behavioral Changes
Reduced appetite 24-48 hours before birth. Hiding in plants or corners. Some females become more aggressive toward males or other fish.
Active labor lasts 2-6 hours and you may see the female "twitch" or quiver as fry are released one by one.
Timing the Cycle
After fertilization, gestation takes 26-32 days at 78°F. Once a female is fertilized, she can store sperm for months and continue producing broods every 30 days without male contact — meaning a single male encounter can result in 3-5 broods.