The minimum size of Silver Arowana fish tank should be 150 cm long, 60 cm wide and 60 cm high. The specific size of fish tanks is determined by their size and feeding density. Generally, the larger the body size and the greater the feeding density, the larger the fish tank needed. It is generally best to raise three arowana. If you raise one arowana, it will be lonely. If you keep two, they will fight. If you raise three, they can restrict each other and grow together.