x1 is a prawn/shrimp [freshwater specimens/species only] of taxon/species/type x2
The term "prawn" is imprecise in English; in Lojban, this word refers to any and only decapod, stalk-eyed, narrow-abdomenned, muscularly-betailed, slender-legged, long-whiskered crustaceans with elongated bodies, that lives in freshwater, and the primary mode of locomotion of which is by swimming (especially propelled by swimmerets); the word is not taxonomic. See also: crimpui