Effect of background color of tanks on growth and survival of juvenile Yellow Seahorse, Hippocampus kuda (Bleeker 1852), in the pelagic phase

Abstract

This communication reports the results of an experiment conducted to see if background tank color affects the growth and survival of juvenile H. kuda. Juveniles were reared from 0 to 21 days after birth (DAB) in one of six tank colors: green, blue, red, or black (dark backgrounds), yellow or transparent (light backgrounds). Growth and survival were significantly higher in the dark backgrounds than in the light (p<0.05). At 21 DAB, the maximum juvenile growth (34.58 + or -1.15 mm, 55.43 + or -6.71 mg) and survival (70%) were obtained in the red, blue, and green backgrounds. The order of growth increment and percent survival at DAB 21 was red > green > blue > black > yellow > transparent and blue > green > red > black > yellow > transparent, respectively. Ingestion of the air-bubble accounted for 65% of the total mortality in all backgrounds and occurred more often in light backgrounds. Juveniles reared in blue and red backgrounds reached a settlement phase on 17 DAB; those raised in the transparent tanks reached this stage at 21 DAB. In conclusion, a carefully chosen background can optimize growth and survival during the pelagic phase of juvenile H. kuda.