I fed my arowana feeders, bloodworms, shrimp, and they LOVE crickets. He also ate pellet food. Great fish, to bad they get so large. You have a bit of time before that fish outgrows your tank. So hopefully by then you can upgrade. That fish can also live upwards of 60 years or more.
Some interesting info I had found when i had my silver:
Care of adolescent arowanas is a little different than that given to small ones. One similarity though is that medium sized arowanas, those up to 14", can often successfully be kept in a community tank with large size non-hostile species such as angelfish, discus, severums, or virtually any other fish this size that would not attack the arowana. Because they are not predatory towards fish they cannot swallow whole, they could still be considered a community fish in a qualified sense.
That community tank which houses a medium arowana had better be large, however, because even a 14" specimen still has quite a bit of growing to do. A 55 gallon tank is a minimum requirement in my estimation. Eventually, a 125 gallon tank would be desirable if the hobbyist wishes to display his valued specimen for the most dramatic effect. An arowana can be contained in a 55 gallon for his entire captive lifespan though, for those hobbyists who want to own an arowana but have nowhere to put a 125 gallon tank.
By this point you may have come to wonder how large your pet ` `leviathan" is going to grow. My own specimen, "Clyde", had reached a length of 20" by 3 years of age and, apparently, was capable of a great deal more growth. He is still 20" at age 8, having been stunted by being kept in a 55 gallon tank all of that time. I have spoken with jungle collectors, sports fishermen, and Game and Fish Officers, and the various estimates, opinions, and experiences I have accumulated place the figure for maximum growth somewhere between 6 and 8 feet.
Grzimer's Animal Life Encyclopedia, Vol. 4 (Fishes I) places the length of arowanas at 60 cm., or about 2 feet, with which I am tempted to disagree. It may be that since the species have been overfished in much of South America because of the encroachments of civilization, large, fully grown specimens have become exceedingly rare. But that does not mean the species cannot attain a size of 6 feet. After all, in the early days of our own country, Maine lobsters of 40 lbs. were not uncommon; whereas today such sizes are unheard of and almost unbelievable.
Our captive arowanas do stop growing, however, at least they do not grow perceptibly after they have reached a certain size determined by the confinement of their aquarium. This is fortunate, because a 20" arowana is hard enough to manage during moving and maintenance. I cannot imagine how a hobbyist could handle a 30" specimen. It would have to be traumatic both for the aquarist and the arowana.
ABOUT THE AUTHOR
Steven Dow, a well-known author of articles and books for the aquarium hobbyist, has been an aquarist for 22 of his 32 years, specializing in the care, breeding, and behavior of fresh water fishes. In addition, he is a sait water aquarist and has been a tropical fish deaier in Orlando, Florida for the past 10 years. Steven Dow has had over 50 articles pablished, most of them dealing with the technical aspects of aquariology for dealers, and has been a columnist for Pet Dealer Magazine tor three years, writing on various subjects of interest to the tropical fish dealer. Steve has published five books including "Your Aquarium", "Your Vacation", "Your Relocation", "Breeding Angelfish For The Hobbyist And Professional", and "Success with Corydoras Catfish." Two more books authored by Steven Dow are scheduled for publication this yeer. In addition, Steve is a Contributing Editor for Freshwater And Marine Aquarium Magazine.
OMG - do you realise how big these fish get? 
Being a prehistic fish, it must have quite the immunities to most disease. It preys on sick, and dieing fish in the wild so this must be the case.
