hmmm... there are two other blacks, a wild silver, a clown knife, two red serverums, a red tail barb, and a few pleco...
i did notice the other blacks picking on it... so it's just that? but they were doing so well not that long ago.. why would they get all aggressive so suddenly...
Arowana are unpredictable and this is what can happen. Anyone who is attempting an arowana community should have other tanks, so aros can be moved as needed.
most likely the other aros nipping at him. ime most aro will do that, sometimes they stop and sometimes they dont... when i first got my three silvers they nipped at eachother for a couple days, now they swim freely with eachother. try seperating the black and any other aro that is being nipped at.
dang... this junk thing is, we got rid of the tank that we had them in previously. We had a new tank that was supposed to be on it's way, but needed the money for an emergancy... so we didn't get to order it yet.. now no more extra tanks...
POOORRR FISH.. I KNEW IT...
THANKS FOR THE ADVICE.. we do have one extra tank.. hopefully we can move it...
but everytime we move them.. they get all beat up so is it safe to move still...
if you are not able to move em try dividing the tank up into sections, isolate the ones getting beat up... just pick up some egg crates (light diffuser panels from home depot) and cut to size and place it into the tank.
You had a try at the the community and it didn't work out. Since you don't have another tank and thats a lot of seperating in one tank to do. I suggest you pick a single arowana to keep, and sell or donate the rest off asap. One arowana should be ok with the other fish. Keep the clown knife well feed and it won't bother the arowana.