ויקרא, פרק י״א, פסוק י״א

God requires people to maintain a strict distance from impure aquatic animals. This separation goes beyond dietary restrictions, establishing a fundamental attitude of disgust and avoidance. Rather than relying on a natural human sense of disgust, this is a Divine command that requires treating these creatures as repulsive. This principle of rejection extends to food mixtures, economic benefits, and anything derived from them [העמק דבר, ביאור יש״ר].

The requirement to view these creatures as repulsive creates strict rules regarding food preparation. If an impure fish or its juices mix into pure food and impart flavor, the entire mixture becomes forbidden. Since fish juice has a sharp and highly dominant taste, strict measurements were established to regulate this prohibition [רש״י, מזרחי, דברי דוד, גור אריה]. Beyond consumption, the primary approach among commentators is that one may not trade or intentionally derive economic benefit from impure fish. This restriction mirrors the laws forbidding trade in animal carcasses, fatally injured animals, and consecrated items [רבנו בחיי, תורה תמימה, הכתב והקבלה, צאינה וראינה]. However, the dietary ban is precise, applying specifically to the flesh of the fish while excluding hard, inedible parts such as bones and fins [רש״י, תורה תמימה, אילת השחר].

A conceptual difficulty arises regarding the instruction to detest the carcasses of these aquatic creatures. Unlike land animals, fish do not require ritual slaughter, nor do they transmit standard ritual impurity when they die [שד״ל, רלב״ג, מלבי״ם]. To explain this, the primary approach among commentators is that the instruction actually broadens the prohibition to include tiny insects and worms that grow in standing water or wine cellars. As long as these tiny creatures remain inside the liquid where they grew, they may be consumed along with it. However, once the liquid is filtered and the insects are separated from their natural environment, eating them becomes strictly forbidden. They are referred to as carcasses because the moment they are removed from the water, their life force ends, and they begin to wither and spoil [הכתב והקבלה, פירושי רד צ הופמן].

Commentators debate the exact nature of these tiny creatures. Some identify them as flying mosquitoes [רש״י], while others argue they are wingless worms that never fly, existing entirely within the liquid [רמב״ן]. An additional perspective suggests that the prohibition targets worms and parasites that grow directly inside the flesh of impure fish or animals [תורה תמימה, מלבי״ם]. Furthermore, the command requires people to reject even the absorbed flavor from these carcasses, ensuring a complete separation from impurity as dictated by God [העמק דבר].