The observations on the post embryonic development of larvae of tawny puffer(Takifugu flavidus)at each stage have been made.The photography and measurement were carried out on their growth,development and behavior ecology.The results showed that the post embryonic development of tawny puffer could be divided into 5 stages,i.e.early larva stage,late larva stage,early juvenile stage,mid juvenile stage and late juvenile stage.Each stage consists of several periods and there are 17 periods in total.The post embryo development lasted for 35 d from newly hatched larva to young fish under water temperature 20.5-26.0 ℃ and the salinity 10.0-13.5.There were 2 key periods of fry feeding habit changing,i.e.initial feeding and ingest artificial feed,and followed by the sequence of feed,yolk,rotifer,Artemia spp. larvae,mediumsized cladoceras,large copepods and cladoceras,benthic,shrimp larvae and artificial feed,etc.Habitat layers of fry are transferred from upper and middle layers into middle and under layers in the water,and their behavior underwent horizontal swimming,cruising and feeding cruising around the pond,three types of swimming behavior.The lowest of specific growth rates of fry were at late larva stage(3.18%/d)and the highest at mid juvenile stage(13.31%/d).The relationship between total length and day age or cumulative temperature could be fixed to the exponential function(y=ae^bx).The relationship of pre-anal length or body height and total length could be described by allometric growth model(y=ax^b).These growth showed two different stages indicated by inflexion points,which appeared at 16-17 d,total length 10.0 mm and 16-17 d,total length 10.5 mm,respectively.Before the inflection point,the growth of preanal length and body height were faster than total length(b＞1),after the inflection point it was slower(b＜1).It is recommended that the larvae of tawny puffer should be fed with Brachionus plicatilis(S-type)with 5-7 ind/mL at 4 days old,fry density should be reduced at 10-12 days old,fry should be transferred from indoor into pond outdoor at about 20 days old and divided to breed by sifting when fry can ingest artificial feed(35 days old)to improve the survival rate in tawny puffer fry rearing.