Larval feeding behavior of Flower fish larva (Blood Parrot × Texas Cichlid) fed Ceriodaphnia quadrangula and Artemia franciscana nauplii in light and dark conditions

Use of planktonic diets especially zooplankton are important in first larval feeding period in fishes. One of the methods for evaluation of larval feeding performance is measuring ingestion rate. In this study, three different live foods, Ceriodaphnia quadrangula, Artemia franciscana nauplii, and combination (1:1 in number) of C. quadrangula and nauplii A. franciscana in light and dark conditions were offered to Flower fish larvae viz 20 (6 mg dry weight) and 40 days (d) (18 mg dry weight) after haching at different prey densities of 2, 5 and 10 ind./ml. Results showed that 20-d larvae of Flower consumed C. quadrangula at a rate of 11.68–43.82 ind./h, A. franciscana nauplii at 36.72–200 ind./h, and mixture of C. quadrangula and A. franciscana nauplii at 18–57 ind./h. Results showed that ingestion C. quadrangula at density of 2, 5 and 10 in./ml for 20-days larvae were 37.05, 11.68 and 16.13 at light, respectively,  and 83.82, 18.73 and 22.26 prey/h/larvae at dark; while for 40-days larvae were 17.92, 60.76 and 23.62 at light, respectively, and 29.79, 58.35 and 37.23 prey/h/larvae at dark. Correspondingly, ingestion of A. franciscana for 20-d  larvae were 139.2, 158.13 and 200  at light, and 36.72, 53.7 and 192.81 prey/h/larvae at dark, these amounts for 40-d larvae were 143.3, 183.57 and 180.84 at light, and 112.15, 181.25 and 205.29 prey/h/larvae at dark. The ingestion  rate increased with increasing age larvae and increasing prey density. The weight specific ingestion (WSI) of C. quadrangula, A. franciscana and its combination ranged 2.5-5.4, 0.54-2.23 and 0.87-2.12 % weight/h for 20-d larvae and 1.37-5.27, 0.34-0.88 and 0.70-1.85% weight/h  for 40-d larvae. The WSI decreased with increasing age larvae. The electivity indices (E) indicating lower tendency towards nauplii of A. franciscana consumption. Based on feeding behaviour, Flower fish larvae could be cultured with two live prey, but suitable feeding performance obtained with nauplii of A. franciscana.