GROWTH, SURVIVAL RATE, AND NUMBER OF MARKETABLE FISH PRODUCED OF GOLD FISH, CARASSIUS AURATUS (L.) IN OUTDOOR EARTHEN PONDS WITH ENDOGENOUS CULTURE OF DAPHNIA SP. OR MOINA SP. AND EXOGENOUS SUPPLY OF MIXED PLANKTON

Prithwiraj Jha

Abstract
   The effect of different management systems on the growth and survival of gold fish in ponds was investigated. Fish larvae (0.11 ± 0.012 g) were cultured for three months. There were four treatments: fish were stocked in outdoor ponds under endogenous culture of Moina sp. (P1), Daphnia sp. (P2), exogenous supply of mixed plankton (P3) and a control treatment where a commercial pellet was applied as food (P4). Values of dissolved oxygen were highest in the P3 (p<0.05). The P4 treatment showed the highest concentrations of NH₄-N, NO₂-N, NO₃-N, PO₄-P, and bicarbonate alkalinity, which were significantly higher (p<0.05) than the other treatments. The final body weight of the gold fish ranged from 3.78 to 7.19 g in the different treatments. At harvest, maximum weight gain was achieved in the P3, followed by P2, P1 and P4 in descending order (p<0.05). There was a significant difference (p<0.05) in the survival of gold fish among the treatments, ranging from 75.77% (P4) to 97.54% (P3). The number of marketable fish was significantly higher in P3 (p<0.05) than other treatments. From the present investigation, exogenous supply of mixed plankton appeared to be a better alternative to culturing goldfish in ponds under endogenous culture of Moina sp. or Daphnia sp.

Key words: gold fish, feed, plankton, growth, survival