鲢鳙杂交种的外部形态,在如下标志方面与亲本比较有显著的差异:腹棱构造,胸鳍长度,头部大小,体色,鳃耙构造等等。杂种的头部小于鳙,而稍大于鲢,占鱼重的25—26%;体色浅,略带金黄,黑素细胞呈黑色斑点,均匀分布体表;腹棱不延伸,未达鳃膜,胸鳍略过腹鳍;当年鱼的鳃弓,每毫米中鳃丝数是10—12,二令鱼是8—9,部分成互生。经比较研究,鲢鳙杂交种的外部形态为亲本的中间型,个别情况下明显地表现出 Silver carp and bighead carp hybrid morphology, in the following signs compared with the parental significant differences: abdominal structure, pectoral length, head size, body color, gill rake structure and so on. Hybrid head less than 鳙, while slightly larger than silver carp, accounting for 25-26% of fish weight; body color shallow, slightly golden, black spots of melanocytes, evenly distributed body surface; abdominal edge does not extend, less than the gill membrane , Pectoral fin slightly over the pelvic fins; then the fish’s gill arch, gill filaments per millimeter is 10-12, two fish is 8-9, some into each other. After comparative studies, the outer morphology of silver carp and bighead carp hybrids is the intermediate type of the parents, in some cases clearly showed