Arowana

1 Species Overview

The arowana is a popular ornamental fish now widely kept as a feng shui fish. In its place of origin it is called AROWANA; the Chinese pronunciation is ‘yaluowana,’ meaning ‘long tongue’ in Spanish. Its scientific name, Scleropages, refers to its tongue-like, bony-tongued form. Taxonomically, arowanas belong to the family Osteoglossidae (also called the bonytongue family). They are widely distributed across subtropical regions such as South America and Australia, and because their body shape resembles the Chinese dragon, they are commonly known as ‘dragon fish’ (long yu).

Arowanas belong to the bonytongue family and are a type of large freshwater fish that already existed as far back as the ancient Carboniferous period. The fish was first described in 1829 in the Amazon basin of South America by the American ichthyologist Dr. Vandelli. In 1933, the French ichthyologist Dr. Bleher discovered the red arowana in Saigon, Vietnam. In 1966, the French ichthyologists Blanc and d’Aubenton found another variety in Phnom Penh. Later, experts from various countries successively discovered additional arowana varieties in Vietnam, the Malay Peninsula, Sumatra and Bangka Island in Indonesia, Borneo, and Thailand, leading to the classification of arowanas into golden arowana, orange-red arowana, golden-yellow arowana, platinum arowana, green arowana, silver arowana, and more. Arowanas were truly introduced into the aquarium hobby as ornamental fish in the late 1950s in the United States, and only became popular worldwide from the 1980s onward.

2 Appearance

The arowana is a freshwater fish that can be divided into several types based on classification, and each type has its own characteristics; specimens of different quality (pinxiang) also differ greatly in price. Using a medium-sized arowana about 25 cm long as a standard, here is a brief introduction to the quality criteria: Coloration — judge the color a given variety should display according to its type; naturally, the more vivid and lustrous, the better.

3 Care Basics

When keeping arowanas, the condition of their shimmering scales reveals whether they are healthy. Scientific husbandry methods and proper lighting that provides natural illumination are also very important aspects of arowana care. Here are some basic arowana-keeping methods.

Research shows that an arowana’s coloration results from pigment cells (chromatophores) in the dermis beneath the scales and guanine on the outermost layer. Various cells are distributed throughout the dermis and can expand or contract with changes in light intensity or environment. Different pigment cells absorb and reflect specific wavelengths of light, so the fish displays different colors under different lighting conditions.

Moreover, an arowana’s displayed color changes with lighting intensity. For example, under strong light the pigment cells expand; as they expand, the pigment radiates outward and the cell area grows, deepening the color — where red pigment is dense, the color becomes deeper and redder.

Conversely, in dim light the pigment cells contract and shrink, the pigment molecules become smaller, and the color visibly fades. At the same time, the pigment concentrates as the cells shrink, sometimes collapsing into tiny spots, so the color naturally becomes pale or faint.

First, change the water weekly. When doing so, prepare the new water in advance and adjust its temperature, pH, and other parameters to match the old water to meet the arowana’s requirements. Do not replace all the water at once — change only 20%–30% each time. When changing water, first siphon out the old water, then slowly pour in the new water along the tank wall.

Second, arowanas need sufficient light. It is best to choose a suitable aquarium light bar and provide 6–8 hours of light per day. Note that natural daylight is still the best light for arowanas; long-term use of artificial lighting can darken their backs. So, if conditions allow, let your arowana get some natural sunlight.

Finally, feed arowanas at fixed times and in fixed amounts. Choose food appropriate to the fish’s condition. Simply put, immature silver arowana fry should be fed small items such as mealworms and bloodworms, while grown arowanas can eat meat chunks, shrimp, and similar foods. Of course, feeding should be varied — combine professional prepared foods with live foods to meet the arowana’s growth and dietary needs.

4 Tank Environment

The most common problem with arowanas is tail-biting and tail-loss caused by fright; many stress-induced illnesses after a fright are difficult to treat. Therefore, providing a quiet, undisturbed environment is very important.

Arowanas thrive in water temperatures of 24–29 °C; strong, healthy individuals can adapt to 22–31 °C. In addition, pH affects their appetite, so pH must be kept stable.

1. Do not place the tank near a door or anywhere people suddenly appear.

2. Avoid noisy or vibrating locations (for example, facing a road with frequent heavy trucks or loud horns).

3. Avoid sudden changes in light intensity. Keep the tank away from windows to prevent strong light flicker; if unavoidable, use thick curtains to block it.

4. Do not exercise vigorously in front of the tank (especially suddenly standing up from below), and do not let red objects appear in front of the tank. When cleaning the glass, avoid the arowana’s head and tail — if it swims over, clean from the other side.

5. Watch out for other pets startling the arowana, especially cats and dogs darting around.

6. When guests visit, politely ask them in advance not to point at or tap on the tank in front of the fish.

5 Feeding

Although arowanas are large, not everything is suitable for them, and they are prone to refusing food, so feeding is a critical aspect of care. In captivity, what and how much to feed is a real skill. Here are common arowana foods and notes on feeding amounts.