One of the minimum appropriate aquarium sizes for arowana is 300 gallons (8′ X 3′). If the fish is young, it is permissible to keep it in a small tank. But when the Arowana grows, a larger one will be needed.
The largest is the Silver Arowana which can reach lengths of 48”. Other variants are the African Arowana and the Black Arowana, both of which can reach lengths of 40” or more. The Asian Arowana, Jardini Arowana and Leichardti Arowana all grow to lengths of 36”. The 300 gallon, 8 x 3 tanks will be sufficient for any of these species.
Of course if you can get a bigger tank that is even better. The size of the aquarium has a direct effect on the well being of the fish. Aside from getting the right aquarium sizes for Arowana, the unit must have a tight cover. An Arowana loves to jump and it may get out of the aquarium.
Arowana fish like soft water with a pH between neutral and 6. Because of their size, powerful filtration is required. Aside from a large tank, there should be a BIO-Wheel and an exterior power filter. There should be no more than 1/4 inch of gravel in it. The ideal water temperature is between 75 and 70 F.
Young Arowanas should be given frozen or live shrimp. They also consume small fish and black worms. If there is space in the aquarium, place several White Clouds in there. As the Arowana gets older and larger, they should be provided bigger fish. Some species of Arowana are known to eat insects.
While filter feeding in aquariums is possible, it is hard. If you are keeping Silver Arowana, you can provide them frogs, beef heart and some insects. However, there are floating pellet food that are made just for these creatures.
If you plan to keep more than one Arowana, a large aquarium will be necessary. Even if the aquarium is spacious, put no more than 5 or 6 Arowanas in it. These creatures can be aggressive. In terms of food, many people prefer the floating pellets to live fish. The reason is the pellet diet are specially created to keep the fish from getting diseases.
In the end, aquarium sizes for Arowana come down to “the bigger, the better”. The more space available, the less likely health problems will affect the fish.