Goldfish, an ornamental fish related to the carp. Goldfish range from 2 to about 18 inches (5 to 45 cm) in length. They were developed in China hundreds of years ago from a brown carplike fish. Many exquisite gold, red, white, bronze, black, and mottled varieties have been developed by the Japanese. Among the unusual varieties are the trailing-finned Celestial, with bulging eyes at the top of its head; and the yellow-gold Lionhead, which has a scarlet head.

Goldfish thrive in water containing lime at a temperature of about 65° F. (18° C.). About 1,000 eggs are laid at mating time, the young hatching in three to seven days. When transferred to lakes or streams, goldfish lose their brilliant coloring and may grow to three pounds (1.4 kg) or more.

GoldfishGoldfish are ornamental fish related to carp.
What Should You Look for When Choosing a Goldfish?

When shopping for a goldfish, you first need to find a good pet shop. If you see a lot of dirty tanks or dead fish in a shop, don’t try to buy a pet there.

Before you pick a pet goldfish, make sure that the fish is not ill. Here are some signs to watch for:

When a goldfish is ill, it may gulp air at the surface, swim in a jerky manner, lie on its side, or rub against objects.

A sick goldfish may also have clouded eyes or fins or gills that are oddly shaped for its breed.

If you buy more than one goldfish, make sure all the fish are about the same size and swim at about the same speed. Bigger, faster fish may harm smaller, slower fish.

What Are Some Unusual Breeds of Goldfish?

There are many unusual breeds of goldfish, with such strange names as the bubble-eye, the celestial, and the pom pom. All three of these fish share one trait that makes them unusual—they all lack a dorsal fin (a fin along the backbone). But, each of these fish has at least one other unusual trait.

When the bubble-eye goldfish is between about 6 and 9 months in age, fluid-filled sacs begin to form around its eyes. By the time the bubble-eye is about 2 years old, these balloonlike sacs can become so large that the fish can have a little difficulty seeing and swimming.

The celestial goldfish has big eyes that bulge out and stare straight up all the time. This breed is also called the stargazer. The pom pom is named for the big, round bumps above the fish’s nose and in front of its eyes. Sometimes the bumps are the same color as the fish’s body, but other times the bumps are a different color.

How Does a Goldfish Know About Its Surroundings?

Goldfish sense their surroundings with sight, smell, and hearing—just like you do.

Because their eyes are positioned at the sides of their head, goldfish see things at the side better than they see things in front of them. They can’t close their eyes, because they have no eyelids. Goldfish, therefore, do not like quick changes from darkness to bright light.

Goldfish smell when water carries odors into their nostrils. Although a fish breathes through its gills, it still has nostrils. Water enters and leaves the nostrils of a fish, but the nostrils do not connect to the fish’s mouth or throat as they do in humans.

Goldfish do not have external ears. Instead, ear bones inside the head and other structures in the goldfish’s body sense vibrations in the water. Goldfish also have special cells on their sides that sense changes in water pressure. Vibrations and pressure changes are what goldfish “hear.”