Goldfish make the ideal aquaponics fish since they produce and eat a large amount of excretion, which provides plenty of nitrate for all of the plants. They are also a fairly hardy type of fish, depending on which species you select, and they can fit the job perfectly.
One important thing for you to know is that there are basically two groups or kinds of goldfish that exist. These are the twin-tailed and single-tailed varieties. Single-tailed goldfish have slim bodies. They are more aggressive and faster swimmers. However, the twin-tailed kind has an egg-shaped body and is very beautiful. Compared to the single-tailed variety, they are less aerodynamically shaped and are slower swimmers.
You need to always keep in mind that you shouldn’t ever mix the twin-tailed and single-tailed species together in the same fish tank. Otherwise, the twin-tailed fish could end up suffering greatly, since they can’t compete very well for food with the more aggressive and faster single-tail fish.
The following is a list of both single and twin tail goldfish varieties to help you better appreciate and understand them as aquaponics fish.
Warning: Don’t mix the twin-tail and single-tail variants in an aquaponics fish tank, and you will be well on your way to having a very productive and positive aquaponics fish experience.
Single-Tailed Goldfish
Common Goldfish
These are among the hardiest of all the goldfish varieties. This is why they are the most recommended goldfish for beginners to start out with. Their bodies are flat and elongated. They live together very well with Koi and are fast swimmers. Common goldfish can live for 10 to 15 years and grow to more than one foot long. You might be surprised to hear that a majority of fancy goldfish varieties actually derive from the common goldfish species.
Comet
This species was originally developed in the U.S. and is very popular there. They are more agile than all other goldfish varieties. They are quite similar to the Common Goldfish, however, their long tail makes it easy to distinguish them. Their tails are also deeply forked and are sometimes as long as their bodies are. Comets are fast swimmers and come in white, red, yellow and orange colors. In the right environment, they can grow to be 12 inches long and live 10 to 15 years.
Shubunkin
These are beautiful fish and have very attractive multi-colored bodies. They are hardy and tough, like most single-varieties are, and are a good option for beginners. They originate from Japan. Given the right environment, they can grow to over 15 inches long. There is a species of blue-colored Shunbunkin that is very valuable and rare.
Double-Tailed Goldfish
Black Moor
This is basically a black version of a goldfish called Telescope Eye. Their bodies are egg shaped like a majority of twin-tailed varieties. This is a hardy fish that’s ideal for beginners to get started with. In well-maintained environments, they can live as long as 15 years and can grow to 8 inches in length. The two main specimens that are available are the ribbon tail and butterfly tail. They are prone to injuries and their eyesight is not very good due to their protruded eyes. Therefore, you shouldn’t place pointy decorations and objects inside the aquaponics fish tank to avoid potential accidents.
Ranchu
This is a very highly regarded and popular goldfish in Japan and China. They look very similar to the Lionhead and are often confused with them. However, the way you can differentiate these two types of goldfish is that the Ranchus have extremely arched backs and shorter tails. When swimming they might look a bit imbalanced since they don’t have dorsal fins. They come in various colors, with the most common being black, red and white or gold. There is also the “tea” color ones, as they are referred to by the Chinese. The Ranchu can grow to 5 to 8 inches in length and live up to 15 years.
Lionhead
There are among the most kept of all the goldfish species due to the distinctive head feature that they possess, which is referred to as the “wen.” It gives these fish a very cuddly and cute appearance. This variety also does not have a dorsal fin. They come in yellow, orange, white (quite rare) and also mixed colors of red and white or black and white. They live up to 15 years and grow up to 6 inches long.
Lionchu
In my opinion, the Lionchu is the most beautiful goldfish without a dorsal fin. The reason is that it incorporates the Ranchu and Lionhead’s best features. It is a crossbreed variant of those two, which is how it gets its name Lionchu. This fish originated in Thailand. It was made popular by goldfish enthusiasts in Singapore. They can live to 15 years old and grow up to 6 inches in length. Their most common colors are white, red, yellow and orange, but are also available in bi-color.
Bubble Eye
There are two bubble-like sacs (or bladders) sitting below their eyes which cause the bubble eye. This is one of the more exotic goldfish varieties. They aren’t recommended for beginners since they require more attention. They have a smooth line from their tail to their head and are dorsal less. These are very fragile fish, and if they are ruptured it could be fatal. They mostly come in orange, however, they are also available in calico, red and white. They grow to 6 or 7 inches in length.
Fantail
These are the western version of Japan’s Ryukin. It is the West’s most popular goldfish and is a very hardy species. They usually have a wide head and short egg-shaped body. They grow up to 10 inches in length and live as long as 15 years. They are very well suited to beginners due to the fact that they are very tough. You can even keep them in outdoor ponds without any significant problems.
Telescope Eye
With a similar build to the Fantail, these fish distinguish themselves by their very noticeable telescopic-looking eyes. Numerous variations of this fish exist, including veiltail, broadtail and butterfly tail, and featured coloring includes shades of white, red, orange, chocolate, tri-color and calico. Living under optimal conditions, these fish can reach 6 inches in length and live upwards of 15 years.
Ryukin
A cousin of the Fantail and hailing from the Ryukyu Islands, this fish is characterized by wide, deep body shape, a pointy head and a dorsal fin that sits higher than most. These fish are known for their active nature and willingness to eat just about anything they are given. They regularly grow to be 8 inches in length and can reach the age of 15 if conditions are right.
Pearlscale
These goldfish are quickly recognizable by their pearlescent scaling and large midsection that many believe resembles a golf ball. Highly alert by nature, these fish can be found in both short and long-tailed varieties. Not the best swimmers, pearl scale goldfish often lose battles with other fish for nearby food. This variety is known for its hardiness among the fancy species and can reach 6 inches of length. Pearlscales are suitable for newcomers to aquaponic gardening.
The above-referenced species really are among the very best choices for those interested in building an effective, healthy aquaponics fish tank environment that includes goldfish.