Comentário sobre Nidá 6:9

קשקשת – the clothing of the fish that is attached to it (i.e., scales).

Whatever has scales has fins, But there are fish that have fins and no scales. For fish to be kosher they need fins and scales. Some fish have fins but no scales, but if a fish has scales, for sure it has fins (see Hullin 3:7).

סנפיר- wings that it flies with them, and whatever has scales, it is known that it has fins and there is no need to examine after it further, for it is a pure fish.

Whatever has horns has [split] hooves; But there are animals that have [split] hooves and no horns. Animals need split hooves to be kosher. Any animal with horns must have split hooves. However, there are animal that have split hooves, such as a pig, but do not have horns.

ויש שיש לו סנפיר – but it is an impure fish, for it lacks scales.

יש לו טלפים - its hoofs are cloven, for there are no horns other than for pure cattle and beasts.

ואין לו קרנים – as for example, swine, whose feet are cloven but they don’t have horns.