A 90 isn't a big tank for that many fish. In my opinion it's over stocked. Have you checked your water with a LFS? Alot of the test kits seem to be doing a bad job of giving us accurate indications of where things are at in our tanks.
I've never kept an arrowana before, but almost everyone I have spoken to who keeps them has had a large tank, IE 180 gallons or larger.
If you want a big tank King Ed just got in an acrylic 300 gallon with stand they're selling for $1700.
Doug
|