Reality Check
Arapaima reach 8-10 feet, 200-400 pounds. Tank requirements: 10,000+ gallons.
Most arapaima die young in inadequate setups. Do not buy unless you have 10,000+ gallon facility.
Wild Range
Amazon basin in Brazil, Peru. Air-breathing fish — gulps atmospheric air.
CITES II listed — endangered, regulated trade.
Diet
Adults eat fish, birds (when available), and mammals when caught.
Captive arapaima eat large fish (whole tilapia), squid, prawns. Massive feeding cost.
Realistic Alternatives
Want large fish? Try arowanas, oscars, large catfish.
Want monster fish? Look at large peacock bass or pacus (still grow huge but more manageable).