Effects of stocking density on the growth rate of gold fish fry reared in hapa

The  present  study  was  conducted  to  investigate  effects  of  stocking  density  on  growth  performances  of  gold  fish  (Carassius auratus)  in  hapas.  Experiment  was  conducted  for  a  month  with  three  treatments  where  three  stocking  densities  were  T₁  (10  fry/hapa),  T₂ (15  fry/hapa) andT₃ (20  fry/hapa)  each  having  three  replications  which  were  selected  randomly.  In  the  present  experiment  hapa (3ft × 2ft × 2ft)   with  1  mm  mesh  net  was  used.  Gold fish  fry  having  a  mean  body  weight  of  0.007 g  were  used  in  all  treatments. Fishes were fed at the rate of 10% of their body weight containing 34.11% protein. Water quality  parameters were monitored at 10 days interval and the ranges were –temperature 24.75 to  27.75 ^oC, dissolved oxygen 3.68 to 4.09 mg/L, p^H  7.3 to 8.16, ammonia 0.3  to  1  mg/L,  nitrite  0.01  to  0.03  mg/L,  phosphate  0.6  to  1  mg/L  and  alkalinity  119  to  187 mg/L.  At  the  growth  performances  were  evaluated  by  comparing  mean  final  body  weight,  specific  growth  rate  and  food  conversion  ratio.  The  present  study  showed  that  the  gold  fish  fry  in  T₁  resulted  the  best  mean final  weight  gain  (1.188 g)  followed  by  T₂  (0.834 g)  and  T₃ (0.686 g).  The  SGR  ranged  between  6.64  and  7.43%  per  day  and  FCR  ranged  between  3.56  and  4.12  with  T₁  showing  the  lowest  FCR.  The survival rate (%) ranged between 76.67% to 85.67%.  From  the  present  experiment  it  was  found  that individual  fish  growth  rate  was  decreased  with  the  increase  of  stocking  density.