Plural of cowfish; multiple specimens of the horn-headed fish species.
Regular plural of 'cowfish' formed by adding '-es' (used instead of '-s' because the word ends in a sibilant sound 'sh').
English's irregular plurals for animal names—'fish' can be 'fish' or 'fishes' depending on whether you're treating them as a group or distinct individuals—reflects ancient grammatical layers still active in our language.
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