The purpose of the present invention is to improve the non-defective rate of a feed for fish farming comprising a feed of dual structure through betterment of the shape of an outer envelope of the feed so as to reduce the possibility of leakage, from both ends of the feed, of a liquid oil contained in an inner capsule. The feed for fish farming of Scombridae family fish an outer shell forming an outer surface; and an inner filling wrapped by the outer shell such that a side surface presents a substantially cylindrical shape and both end portions are covered and closed by the outer shell, at least one of the both end portions being formed with a protruding portion having a tapering shape in which the outer shell protrudes toward the end portion.