I was in Manous Brazil about 2 years ago where Arowanas are often sold as food in the local fish markets. You can buy a 2 ft one for around $3, and I heard the price has gone up as the get harder to find. The unfortunate part is that if we ever try to restock these fish in the Amazon they will only be eaten. If I was an Arowana I'd rather be in a tank of any size than on a dinner plate. Food for thought ---
Just want to contribute my point toward this subject of tank size.
Certainly, to keep arowana happy (you should release them into the wild) because no one can provide such a big 'tank' in the house/apartment no matter whether it's 4ft or 8ft for that matter....It's still way too small and I guess member should agree with me on this point?
As a hobbylist myself, tank size is important but equally critical is how committed you're to maintance the correct water parameters, the food and others requirement for the fish you're keeping.
I often see big and beautiful asian arowana keeping in the 4ft or 5ft tank with top-of-range filteration system, feed them the daily live food and their time and committed to raise it is unbelievable. I can see those heathly and beautiful fish lives very comfortably with their 'cage' tank in the water which is unbelievably crystal clear and healthy. If the fish has not been adjusted nicely in such a small space, it could have been died and deform long time ago.
All good points, I always hear that a 300 gal, is needed to house an adult silver for life, it's good you are doing research, I think that the width is important make sure they can turn comfortably and have a fair amount of length to swim, it seems that people have varying amounts of success with different size tanks so keep learning and let us know what you end up doing!! good luck!!
I know this question is always debatable, but am becoming very intrested in arowanas and would like to know, what is the minimum tank size to keep any arowana?
In my opinion all aros at full size need a 3' foot wide tank; South America aros would be better off with 4' foot wide tank. The length should be a least 6' feet and height should be at least 2' feet. Be prepared to SPEND ALOT OF MONEY before you buy an aro!!!