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How Often Do GloFish Lay Eggs?

GloFish come in vibrant fluorescent colors such as red, green, blue, orange, purple and pink. They are genetically engineered zebra danio fish, also known as zebra fish. Scientists placed a naturally occurring fluorescence gene in the zebra danio, which resulted in the vibrant colored fish seen today. GloFish currently breed without the help of scientists. The vibrant color is inherited from the parents and is passed on to future generations.

Courtship and Egg Production Frequency

A female GloFish releases pheromones that initiate courtship behavior in the male. The male releases gonadal pheromones, causing ovulation to occur in the female. Female GloFish have the capability to lay eggs every two to three days. A single clutch can contain up to several hundred eggs.

Signs of Eggs in Female GloFish

Females will show physical signs that they are carrying eggs. A swollen belly is the most noticeable symptom. Many pet owners confuse the swelling of the abdomen with pregnancy. GloFish are not live-bearers and therefore can't be said to undergo pregnancy. Females will release eggs in the presence of males.

Egg Fertilization

Female GloFish release their eggs by dropping them into the water, usually at a spawning site or as they swim throughout their fish tank. Once the female releases the eggs into the water, males fertilize the eggs as they fall to the bottom of the tank. Since GloFish spawn in spools, eggs from one female can be fertilized by more than one male.

Survival of Eggs

Survival of fertilized eggs is minimal. Most are consumed by the adult GloFish almost immediately. Many fish owners add marbles to the bottom of their fish tanks to protect the fertilized eggs. The marbles leave small gaps open for the fertilized eggs to bounce or slide into, where they are shielded. It takes up to two days for the eggs to hatch and an additional two to three days after that for the fry to swim out in search of food.