questions: aksed about the optimum size,depth and shape of fish pond. 
 answers: given as nursery pond: 100- 500 m2, 1.0- 1.5m, rearing pond: 500- 1000 m2, 1.5- 2.0m, stocking pond: 1000- 2000 m2, 1.5- 2.5m.