Dear Adrian,



We have already answered this question in the past (see The Sages erred and misled about the signs of kashrut in fish and its < a href=https://daatemet.org.il/questions/index.cfm?MESSAGEID=491>response as well as About the fish which has no fin, the Monopterus cuchia).



Now we have to add three more points:

a) The “rudimentary dorsal fin” of Monopterus cuchia is nothing more than a ridge of skin which does not even possess fin rays. There is no reason to consider it a fin any more than the human tailbone (coccyx) can be considered a tail.

b) It is not likely that the dorsal fin (even when fully developed) would count as a “fin” under the Halakhic requirements, since the Mishnah in Chullin 3:7 describes fins as “[those] by which the fish moves,” which can apply only to the pectoral and the pelvic fins.

c) In fact, beside Monopterus cuchia, there is a whole group of aquatic animals which have scales but no fins — sea snakes (please note that the Torah’s criteria of fins and scales are applicable to all aquatic creatures according to Leviticus 11:9-12 and Deuteronomy 14:9-10). On the other hand, it is not clear whether the scales of sea snakes answer the Halachic requirements for scales.

For more information on this issue, see Nosson Slifkin, The Camel, the Hare and the Hyrax: A Study of the Laws of Animals with One Kosher Sign In Light of Modern Zoology (Southfield, Mich./Nanuet, NY: Zoo Torah and Targum/Feldheim, 2004), pp. 216-219.



Daat Emet

Dear Adrian—



We do not consider it likely that Monopterus cuchia is kosher. Look once again at the definition of fins in Mishnah in Chullin 3:7: “[those] by which the fish moves.” Now, this obviously cannot apply to the rudimentary dorsal fin which Monopterus cuchia possesses. Other fins (viz., pectoral and ventral) are present in Monopterus cuchia only in the larval stage – the stage during which the fish’s organism is not yet fully developed and undergoes a development similar to that undergone by embryos of mammals (for example, larvae of Monopterus cuchia have a yolk sac). When the larvae reach the stage of full development – 10 days after hatching out of an egg – the pectoral and the ventral fins disappear, as does the yolk sac. But even in the larval stage, the pectoral and the ventral fins are used by the larvae not for movement but for respiration: prior to the development of gills, gaseous exchange takes place in the vascular system of the fins. Movement of the fins creates a smooth water current over the body of a larva, enabling a better utilization of water for oxygen, but does not enable the larva to move its own body [see B. N. Singh et al., “Respiratory Adaptations in the Larvae of Monopterus cuchia (Ham.),” Journal of Fish Biology 34 (1989), pp. 637-638].

Thus, there is no reason to consider the larval fins of Monopteruc cuchia as kosher fins; and we would be very surprised if some Halakhic authority ruled Monopteruc cuchia to be kosher.

Besides, sea snakes (aquatic animals who have scales but no fins) are different from eels. The zoological classification of the sea snakes is: Kingdom Animalia, Phylum Chordata, Class Reptilia, Order Squamata, Family Hydrophiidae, while that of the eels is: Kingdom Animalia, Phylum Chordata, Class Actinopterygii, Order Anguilliformes (search these out in http://en.wikipedia.org). And as noted in the book of Rabbi Nosson Slifkin, which we recommend you once again, the scales of sea snakes are detachable under certain conditions.

In sum, Chazal’s rule that “everything which has scales, has fins” does not apply to all aquatic animals.



Daat Emet