Lots of different possibilities as to the disappearance of your aro. This is why it is recommended that small arowana be kept by themselves until at least 6" or so. Was this a silver aro?
im going alittle off topic but close .... i had the same setup as bboykoi and i also lost a arrowana when they were 3 inch and now the one Silver arrowana i have left is 15 inch long, do u guys think i would be able to introduce another silver arrowana.... they'll be going into a 210 gallon tank... thanks for the input
giant gourami is the only problem i see
they are nasty
you need a big big tank or lucky that they dont kill aro.
my giant gourami was way smalle rbut harassing my jardinii ..... thye are nasty