ventral fin

基本解释

By 30 days, the bud of ventral fin appeared;
孵出后第30天，腹鳍芽出现；
Dorsal fin , tail fin and fat fins slightly yellow, pectoral fin , and ventral fin Tunqi gray.
背鳍、脂鳍和尾鳍稍带浅黄色，胸鳍、腹鳍和臀鳍灰白色。
The design is a nod to freshwater knifefish, which can move forward and backward, and hover, by rippling an elongated ventral fin.
Gymnobot的设计灵感来自于一种名为宝刀鱼（knifefish）的淡水鱼，这种鱼利用腹部长长的鱼鳍，在水中可以进退自如，还可以作出水中盘旋等动作。