The feeding trial duration was 42day (6week) and was determined by all the treatments achieving greater than 500% weight increase. Fish were fed twice daily to apparent satiation and feed intake was recorded. No time limit was placed upon satiation feeding and continued until the fish in each tank stopped consuming pellets. Uneaten feed was removed, dried, and weighed. Weight gain and survival were determined every other week. Temperature was monitored daily with an infrared thermome- ter (29±1C), while total ammonia nitrogen (ammonia salicylatecyanurate method; range 0.0–0.6mg/L) and pH (Accumet AB15; Fisher Scientific, Pittsburgh, PA, USA; range 7.0–7.8) were measured biweekly. Water calcium content was adjusted to 80mg/L with calcium chloride and alkalinity adjusted to 95mg/L with sodium bicarbonate prior to stocking fish. Salinity was adjusted to 2g/L with sodium chloride.