Meet the Goldfish

Many varieties of goldfish are available as pets, but all of them belong to a single species, Carassius auratus, that was originally found in China more than 1,000 years ago.

The goldfish as we know it today doesn’t exist in the wild but is thought to have first been bred by the Chinese from natural mutations of the wild goldfish. The original goldfish still exists in rivers, lakes, and sluggish streams in China but has a somber olive color that helps it blend in with the murky waters. (The young of most domestic goldfish start life with this same coloring, and attain their bright colors after about a year.)

Goldfish come in more than 100 varieties that differ in size, color, shape, fin type, and other features. The following are general descriptions of several of the different goldfish you can choose from to add to your aquarium.

These single-tailed goldfish are the easiest variety for beginners to keep. Commons can reach 8" (20.3 cm) or more in length. The body is sturdy with a smooth outline; the fins are erect; and patterns are clear, balanced, and extend to the fins. Common goldfish can be one solid color or a combination of colors, and solid-colored commons may be red, orange, yellow, blue, brown, or black.

Feeder goldfish, or goldfish bred specifically as food for other, larger fish, are a type of common goldfish. Don’t purchase feeder goldfish to add to an aquarium, however—they are typically malnourished and unhealthy at the time of purchase and aren’t meant to be pets.

These colorful goldfish are similar in shape to common goldfish but usually have longer tail fins, which are always single. Depending on the subtype, they can range in length anywhere from less than 5" (13 cm) to more than 8" (20 cm). The base color is blue, with patches of violet, red, orange, yellow, brown, and numerous black spots. There are several subtypes of the shubunkin. The London shubunkin, for example, is identical to the common goldfish in body shape and finnage, while the Bristol shubunkin has longer and more developed fins.

Color in any shubunkin may take two or more years to become fully established and changes frequently during this period. Young fish with bright colors may become duller and muddier with age, and fins that were once long and flowing may become heavy and out of proportion to the body.

By far the most common goldfish seen in pet shops, millions of comets are kept as pets. Slightly smaller than the common goldfish, comets have a single forked tail fin and a long, slender caudal peduncle (the part of the body to which the tail fin attaches). They are extremely fast swimmers and aggressive feeders and so should not share a tank with slower, heavy-bodied fish that are unable to compete with them for food.

Young comets are usually a drab olive-gray color, but as they grow, they take on their adult coloration, which may be a deep orange, red and white, black, red and black, white, or calico (multicolored).

One of the most popular and inexpensive varieties, ryukins can grow to about 8" (20.3 cm) in length. They have a deep body that slopes steeply from behind a long and distinctly pointed head. They have a high dorsal fin and a long tail fin with three or four lobes. Ryukins are available in the full range of goldfish colors, especially red, red and white, red and black, and calico.

These goldfish are characterized by a spongy, bubbly head growth known as a wen. Ranchus lack a dorsal fin and have a steeply arched back and a fully divided tail fin that faces almost downward. They can be solid or multicolored, and there are also some nacreous (pearlescent) varieties, including sakura nishiki, which is red and white, and edo nishiki, which is calico.

Lionheads look similar to ranchus except that the lionhead’s back slopes gently and smoothly toward the tail.

One of the largest and most varied breeds of goldfish, orandas can reach a length of 10–12" (25–31 cm). The body is short and high, with fins similar in appearance to those of a ryukin. They come in a variety of colors, including solid red, red and white, orange-yellow, blue, bronze or chocolate, and calico. Orandas also have wens, but they seldom appear as strongly developed as the wen of a lionhead or ranchu.

The celestial goldfish’s most distinctive feature is its eyes, which protrude from the top of the head and gaze permanently upward. A celestial has a long, tapered body that can grow to more than 9" (23 cm) in length and lacks a dorsal fin. The distinctive upturned eyes are not present at hatching—young celestials look much like other goldfish at a young age—but the eyes start to migrate around the head as the fish matures. Celestials are typically colored in combinations of red, yellowish orange, and white.

The bubble-eye goldfish has a similar body shape and fin arrangement to that of the celestial: It has a deep body, lacks a dorsal fin, and its back slopes toward a clearly divided and forked caudal fin. All other fins on the bubble-eye’s body are paired and have rounded edges. These fish can reach a length of about 8" (20 cm) and are usually red, red and white, black, bronze, calico, or blue.

The bubble-eye takes its name from the extremely overdeveloped, fluid-filled pouches of skin under and around the eyes. These sacs vary among individual fish in both size and thickness (usually, a larger bubble has thinner skin) and continue to grow throughout the fish’s life if properly cared for. Large bubbles are often weighty, forcing the fish to spend much of its time on the floor of the aquarium and making it difficult for a bubble-eye to compete with sleeker, more streamlined fish for food.

All goldfish varieties other than commons, shubunkins, and comets are generally classified as fancy goldfish. Although there are more than 100 varieties of goldfish bred in various parts of the world, fewer than a dozen are likely to be available in your local pet shop. In many areas, only five or six are available. Most fancy goldfish types have several subtypes or related variances that differ in minor features.

The more a type of goldfish differs from the norm, the more likely it is to need extra care. Exotic goldfish with particularly long fins, unusually shaped bodies, or enlarged, protruding eyes are not recommended for beginners.

Goldfish vary in personality among individuals and different types, but in general, they are peaceful, social fish that thrive in tanks with other goldfish. However, goldfish are aggressive, opportunistic feeders that grab whatever food they can get as quickly as they can. When keeping a goldfish with other fish, it’s up to you to make sure that everyone in your tank is getting enough to eat.