The male goldfish show signs of white pustules on their gills during this time, whilst the female goldfish do not. The mating season of goldfish can occur at the following times:
- After the age of four months old
- Four to five months after being introduced into a tank or aquarium
If two goldfish are the same age, the fins can also give a clear indication of the sex of the goldfish. If the fin is longer, then the goldfish is a male. The body of a male goldfish is also generally longer than that of a female. The female body of a goldfish is more rounded, and the fins are normally shorter.
Goldfish are a freshwater fish and are the most common form of domesticated fish. They were first kept as pets in China and vary greatly in size, shape and color. Most goldfish are orange, although it is not uncommon for goldfish to have elements of red, brown, yellow and black.
A goldfish can live for up to 10 years and they can be kept safely as pets as long as certain important procedures are followed. The most important procedures to follow when keeping them as pets are:
- Change the water regularly as this will prolong the life of the fish by reducing the chance of infection
- Keep an eye out for fish that are introduced to the tank, they can be bullied by the other fish
- If the fish are bullied by others, then the bully should be removed from the tank