Abstract:Body pigment and band are important morphological characteristics of fishes.Pigment variation and band formation during early development are extremely important metamorphic traits,marking the qualitative changes from one stage to another in early development of fish.The formation and changes of fish body color is the result of adaptation to environmental change.It is the important embodiment of environmental change and health,along with the environment,age,health status and physiological changes,fish body color changes accordingly.For understanding the changes of important morphological characteristics during early life stages of Oplegnathus fasciatus,complete artificial propagation and seedling pond rearing were carried out in Raoping,Guangdong Province.Body surface pigment variation and band formation during embryo,larva,juvenile and young of O.fasciatus were observed,and the frequency of bands formation at different life stages was calculated.Results showed that three kinds of pigment cells were found in a chrysanthemum shape,including melanophore,xanthophore and brown pigment.Pigment could be observed in embryonic stages,their appearance and transformation run throughout the early development stages.Pigment cells in embryo and newly hatched larva were small in size,branches short and few,with rare and even distribution,leading light and transparent in body color.With the development of larva,pigment cells increased in size,longer in branches,and some of them connected in net-shape.In late larva stage,especially in band formation period,chrysanthemum shape pigment cells were found to be more,denser and shorter in branches,distributed densely,resulting in deep color on the body.The pigment band development was divided into 8 stages,corresponding to that of non-pigmented band and formation of 7 pigment bands,respectively.Pigment bands appeared first on the head and abdomen at the same time,corresponding to the 3 chrysanthemum shape pigment on anterior 3 pigment bands.The period from 12d to 16d was the formation stage with pigmented cell accumulation.At the water temperature ranging from 22 to 27℃,first band could be found at 17d after hatching,and 7 bands all formed up to 32 d after hatching.Formation of 7 pigment bands was developed in sequence:3rd band→4th band→2nd band →1st band→5th band→6th band→7th band.Adult fish colored in black from rostrum to eye,black or brown in margin of caudal fin,changeable in body color,white in body in general,becoming yellow-brown when stressed.In conclusion,formation of bands is the important metamorphic trait in larva,juvenile and young of O.fasciatus.Occurrence and sequence of pigment bands vary with the species.Generally,formation of all bands originated from occurrence of one or several pigment cells.