Ruling 1829 — The One-Fifth Tax (Khums)

If a person purchases an animal and finds some property in its stomach, in the event that he deems it probable that it belongs to the seller or the previous owner, and they had disposal over the animal and over the object that was found in the animal’s stomach, he must inform them about it. After that, if he does not find an owner for it, in the event that its value reaches the niṣāb of a treasure trove, he must pay khums on it. In fact, based on obligatory precaution, he must pay khums on it even if its value is less than the niṣāb; and the rest is his property. This rule also applies to fish etc., provided that it was looked after in a particular place and somebody undertook to feed it. However, if the fish was caught from the sea or a river, it is not necessary to inform anyone.