Many goldfish owners often wonder if they will be able to tell if their goldfish are pregnant. They get excited to think of little goldfish swimming around the tank. They then realize they do not even know how to tell the difference between the males and females.
To begin with, goldfish are not livebearers, they lay eggs. This means they do not produce live babies. This also means that goldfish do not get pregnant. The breeding process can be complicated and owners who understand the process will better understand their goldfish.
To begin with, it is obvious to have a mix of male and female goldfish in order to produce babies. Determining the sex of the goldfish can be difficult, but there are characteristics that can help distinguish the difference.
Males are generally smaller and have firmer stomachs than females. Pectoral fins of a male goldfish are longer. Pectoral fins of a female are shorter and rounder. When female goldfish are ready for breeding, their stomachs will become rounder due to their stomach filling up with eggs.
Some people believe this is how you can tell if your goldfish is pregnant. Males develop white breeding tubercles on their gills during this same period.
The breeding process can be fascinating to watch and it may appear that the female goldfish could become pregnant in the process. However, the female actually lays eggs in clusters and the male swims over the eggs releasing sperm to provide fertilization.
Carefully watch the goldfish for changes in behavior. If egg deposits are noticed, they should be removed from the tank and isolated from the other fish. The eggs will normally stick together and be easy to detect. If the eggs are left in the tank, other fish will likely eat them.
Keep in mind the eggs need to be placed in a separate tank with a filtration system. A sponge or under gravel filtration system works best. This way when the eggs hatch, the fry cannot be sucked up into the filter.
After a short period of isolation, little fish will begin swimming in the new tank. If this happens, the breeding process was successful. It is perfectly normal for only some of the fry to survive.
It is best to feed the new fish powdered fry food or brine shrimp. Keep the tank clean and enjoy the view. Next time the question of pregnant goldfish is brought up; you will not have to think twice about the answer.