The Silver Arowana is a truly Jurassic fish. It looks like a dinosaur and sometimes acts like a dinosaur. They reach ridiculous proportions in the wild, however aquarium specimens are said to rarely reach three feet. Mine is just less than two feet and its growth has certainly slowed, Im not quite ready to say it has stopped though. If you are considering getting one of these fish then its length needs to be taken into consideration. My aquarium is six feet long and it seems sufficient. I would never consider putting one in anything shorter. This fish needs room to swim. Despite its size however mine has a turning radius of no more that eight inches. Ive read other owners say that if the Aro is forced to swim backwards too often (from lack of swimming space) its gill covers can begin to curl outward. Ive never seen this but I can imagine that its possible because the Aros gill covers are very delicate.
My Aro is not aggressive toward his tank mates, only his dinner. He chomps at any type of food with tenacity. Its a good idea to put the food in when hes on the other side of the aquarium, otherwise Id probably get wet. In contrast, this fish will take down a good sized goldfish, yet has never even nipped at my three inch Silver Dollars. I keep thinking that one day they will start disappearing but it hasnt happened. Sometimes my Aro gets picked on my Oscar, he never fights back. Arowanas are definitely jumpers. Mine has been on the floor twice. He didnt need any kind of running start to get 15 feet away from the aquarium. Both times he jumped it was during water changes. I think this fish is claustrophobic. The tube from the siphon can seriously limit the swimming space and if I dont keep it out of his way he gets nervous. Picking this fish up off the floor is no picnic. They have razor sharp teeth and powerful jaws, in that sort of panic they will try to bite you. Be very careful. I once read online that its a good idea to pet your Aro from time to time so that it becomes used to your hand in the aquarium. This is ridiculous. My Aro is a runner, not a fighter. If I agitated him in this way I am sure that hed take off. Just by my own observation, Id say that these fish need to be swimming to breathe properly. My Aro NEVER stops moving.
My Aro is at least as susceptible to disease as my Oscar. Shortly after I got him he developed fin rot. With a week he had no fins at all. One month of Melafix had him back to normal though. When my Oscar got HITH, my Aro got HITH. After treatment, my Oscar's hole healed up nicely. The Aro still bears the scars. Arowanas are also very likely to get Drop Eye. This is a condition where one or both of the fishs eyes turn a few degrees downward and become fixed there. There is some controversy as to whether or not this is indeed a disease. Arowanas caught in the wild never have this condition; however it is very likely (better than 50% likely) to show up in the aquarium. It does not affect the fishs overall health and therefore is in no way life threatening. Its very likely to be a genetic issue from inbreeding at fish farms. My Aro has one drop eye. It hasnt impacted his ability to see and swim gracefully so Im not worried about it. Of the cures you may see on the internet for drop eye, Ive found them all to be bogus.
Are Arowanas suitable tank mates for Oscars? Yes and No. Ok... mostly no. These fish get HUGE. Mine is two feet and may or may not get much bigger. They produce at least as much waste as an Oscar. Heavy filtration is a must. As for all Oscar tank mates, youre going to have to try it for yourself. I keep a vigilant eye on mine to make sure that he isnt getting bullied. My Aro has never stood up for himself. He just needs to be able to keep his distance if he needs to. If you are going to keep one of these amazing fish, prepare for a lot of work, on a large aquarium. You want a tank thats at least 6 feet long with a heavy lid or something you can strap down. They appreciate strong currents near the surface, and plenty of oxygen in the water. This fish isnt at all picky about the water he is in as long as it is clean. Keeping one with less aggressive fish wouldn't probably be all that difficult for the seasoned aquarist. Keeping one with an Oscar is a delicate balancing act. If you're the type of person who's new to keeping fish, I'd leave this monster at the store.
Article by MNielsen