Weekly 30-50% Change
For tanks 500L+ with 1-2 arowana, 30% weekly is minimum. 50% is ideal for color-focused keeping.
Smaller tanks (under 500L) need 50% twice weekly. Arowana excrete heavily and nitrate climbs fast.
Dechlorination Protocol
Use a concentrated dechlorinator that neutralizes chloramine, not just chlorine. Cambodia tap water sometimes has both.
Prime, Ultimate, or Kordon NovAqua all work. Dose for the full tank volume, not just new water, for safety margin.
Temperature Matching
Replacement water must be within 1°C of tank water. Sudden temp drops cause arowana to flare gills and potentially flip.
Use a heater in your water prep container during cool season. Test with thermometer before adding to tank.
After-Change Observations
Arowana often feed heavily 30-60 minutes after a water change — a sign the change was beneficial. Lethargy after change means parameters were off.
Log pH and TDS before and after to track trends. Big parameter swings indicate tap water has changed or filter is degrading.