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Hi all. I have a Asian arowana ~16 years of age, ~18 inch. Diet: Superworms + Crickets (usually up to 18 per day combined) PH: 7-7.2 Recently (6 days ago) I did a 20-30% partial water change. Usually he will only eat 2-3 days after the water change. (Water change done every 1.5 weeks) Water...