Kosher fish comes down to one rule from the Torah: a fish is kosher only if it has both true fins and removable scales (Leviticus 11:9). Everything else is a detail that flows from that test. These guides explain the rule and the cases people find confusing.
Start with the rule
Almost every fish has fins, so scales are the deciding feature. A kosher scale has to be visible and removable without tearing the skin. That single point explains most of the fish people ask about, from catfish to shark to shellfish.
The guides in this section
- Why sharks, catfish, eels, and shellfish are not kosher · the species people ask about most, and the reason each one fails.
- Bottom feeders: why they can still be kosher · why where a fish eats does not decide its status.
- Commonly confused fish and the mistakes to avoid · the name swaps and label tricks that catch people at the counter.
For a quick lookup of any specific fish, use the search box on the homepage. For a binding answer on an unusual fish or preparation, ask a trusted rabbi.