Birth and Immediate Rescue
Pregnant females show a dark "gravid spot" near the back of the body that grows larger and almost black before birth. Watch for hiding behavior, refusal to eat, and a square belly shape — birth is within 24-48 hours.
Move the female to a separate birthing tank or breeder box 1-2 days before birth. After delivery, return her to the main tank immediately — she will eat her own fry within minutes.
First Foods (Days 1-7)
Newly hatched brine shrimp (BBS) is the gold standard — fry can eat them on day 1. Crushed flake food works as backup. Feed 4-5 small meals per day.
Microworms and vinegar eels are even smaller and great alternatives. Live food triples growth rate compared to flake-only diet.
- ✦Hatch BBS daily — it loses nutrition within 12 hours.
- ✦Add a sponge filter — bare or fine sponge prevents fry suction.
Weeks 2-6 — Growth Phase
Continue BBS once daily. Add crushed pellets and tiny daphnia. Daily 25% water changes keep ammonia down and stimulate growth.
Sex differentiation begins around week 4-6 — males develop a gonopodium (modified anal fin) and start showing color. Females remain plain.
Weeks 7-12 — Color Development
Males develop full color by week 8-10. Females reach maturity around week 10-12 and can become pregnant if males are present. Separate sexes at week 6 if you want to control breeding.
By 3 months, fry are sellable size. Healthy guppies grow to 1.5-2 inches body length and live 1.5-2 years.