The Law Code of Devala 2.3: Kṛtyakalpataru · Gṛhastharatnākara · Mahānibandha +1

2.3

śambūkaḥ śuktir nakhaśuktiḥ śiśumāraḥ plavaṅgamaḥ | matsyāś ca vikṛtākārā naiva bhakṣyā jalaukasām

“Revered sir, how indeed may Brahmins, Kṣatriyas, / Vaiśyas, and Śūdras in order attain purification when carried off by Mlecchas?

Of water creatures, snails, oysters, nail-shells, porpoises, frogs and fish of misshapen form are not to be eaten.