Jardini & Leichardti Arowanas: Jardinis and Leichardtis are both Australian arowanas; they are not the same species but will be grouped together for this post. Jars & Leis do not develop DE as often as silver arowanas, but the majority of them do after hitting 16"-18". Asian Arowana: The Asian arowana has a very low chance of getting DE. However, the key to a thriving aquatic community lies in choosing suitable tank mates for your Arowana. To ensure a harmonious environment, we’ve compiled a comprehensive list of ideal companions for your Arowana. Let’s explore each one in detail! 1. Silver Dollars. Silver Dollar. fish, make excellent aquarium fish, Fish Spotlight: Silver Arowana. Arowanas are one of the most sought after predatory fish in the aquarium hobby and are believed to date back over 100 million years. There are six species of true Arowanas, but many of them are restricted by some states. The one most readily available is the Silver Arowana. The Silver Arowana inhabits the Amazon Most of the hobbiest of aquariums has a facination to keep an Arowana. It might be Silver or Asian. It varies over their taste. All though they have them Size. The typical size of a Silver Arowana in captivity is almost 3 feet long when fully grown! These are massive fish. In the wild, they’re known to get even larger. Specimens that are nearly 4 feet long have been recorded. Author Note: Size is one of the biggest obstacles that fish owners have to overcome. Arowana is a monster fish. As such, it should only follow that a monster fish needs a monster tank. The absolute minimum tank size for a solitary arowana (with possibly a few tank mates) is: 220 gallons (6’ x 2.5’ x 2’) for a South American arowana. 120 gallons (4’ x 2’ x 2’) for an Asian or Australian arowana. Colorado. Dec 10, 2007. #1. I have two 24-25" silver arowanas. I do beleive that I have a male and female. The physical traits that differ between the two. Jaw structure (Credit to JohnPTC), the one which is believed to be the male has a boarder jaw that extends above the head and is at less of an angle compared to the female. This Arowana Fish thrives in temperatures between 75 and 86 degrees Fahrenheit (24-30 C), and pH between 6 and 7. Young Silver Arowana should not be in a tank shorter then 36 inches/ 90 cm, and as they get older, 48 inches/ 120 cm though when your Arowana fish reaches 15 inches/ 40 cm they will need a much larger tank. PdQop4.