michin.

Īca pāquizqueh; īca ahāhuiyazqueh in notlahhuān, tlamacazqueh, Chicōmahtlapalehqueh, Tezcaīxehqueh, Quetzaltēntzonmāxaliuhqueh, Iztāqueh Tlamacazqueh = With it my uncles, the priests, Seven-fins-owners, Mirror-eyes-owners, Those-with-divided-plume-beards, White Priests [i.e., the fish], will be happy; with it they will have pleasure
(Atenango, between Mexico City and Acapulco, 1629)
Hernando Ruiz de Alarcón, Treatise on the Heathen Superstitions That Today Live Among the Indians Native to This New Spain, 1629, eds. and transl. J. Richard Andrews and Ross Hassig (Norman and London: University of Oklahoma Press, 1984), 113.

michnamacac in itequiuh ce tomi = The fish sellers' tax is 1 tomín (Coyoacan, mid-sixteenth century)
Beyond the Codices, eds. Arthur J.O. Anderson, Frances Berdan, and James Lockhart (Los Angeles: UCLA Latin American Center, 1976), Doc.25, 138–139.

ma ticcohuacan yn tetl. yn quahuitl. ma yehuatl yca. yn atlan chaneque yn atlan onoque ӯ michin yn axollotl yhuan in cueyatl. yn acocillin. yn anenez yn acohuatl. yn axaxayacatl. yn izcahuitli. yhuan yn canauahtli yn quachilli = yn yacaçintli. yn ixquich yn totome yn atlan chaneque = Let us buy stone and wood by means of water life, the fish, salamanders, frogs, crayfish, dragonfly larvae, water snakes, waterfly eggs, and red shellfish that live in the water; and the ducks, American coots, all the birds that live in the water. (central Mexico, early seventeenth century)
Codex Chimalpahin: Society and Politics in Mexico Tenochtitlan, Tlatelolco, Culhuacan, and Other Nahuatl Altepetl in Central Mexico; The Nahuatl and Spanish Annals and Accounts Collected and Recorded by don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, eds. and transl. Arthur J. O. Anderson and Susan Schroeder (Norman: University of Oklahoma Press, 1997), vol. 1, 106–107.

auh ynic niman ompa ontlacallaquiaya azcaputzalco cencuauhchiquihuitl cueyatl no cencuauhchiquihuitl michin = and the Culhuaque provided the Mexica with a heart for their altar. It was of excrement and whippoorwill feathers, wherefore the Mexica where much saddened.
Codex Chimalpahin: Society and Politics in Mexico Tenochtitlan, Tlatelolco, Culhuacan, and Other Nahuatl Altepetl in Central Mexico; The Nahuatl and Spanish Annals and Accounts Collected and Recorded by don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, eds. and transl. Arthur J. O. Anderson and Susan Schroeder (Norman: University of Oklahoma Press, 1997), vol. 2, 30–31.

Quen uel ximimatia in titeocuitlamichin. Iquac mitoa: intla aca quin yeoa uel monemitia, zan tepan itla ipan uetzi. = What happened to you, fish of gold? Be careful! This is said when someone had lived a life of propriety until a certain time and then something came over him.
Thelma D. Sullivan, "Nahuatl Proverbs, Conundrums, and Metaphors, Collected by Sahagún," Estudios de Cultura Náhuatl 4 (1963), 114–115.

michin (fish) could be used to refer metaphorically to a warrior, linking references to "the other world as a watery paradise" (late sixteenth century, Tetzcoco?)
Ballads of the Lords of New Spain: The Codex Romances de los Señores de la Nueva España, transcribed and translated by John Bierhorst (Austin: University of Texas Press, 2009), 36.

ma mocujtlapan xocontlali in chilҫolotl, in jztatapalcatl, in tequjxqujtlaltzin, in mjchtlaҫultzin: ma xoconmotlatoctili in aoacan, in tepeoacan = Place the strands of chili, the salt cakes, the nitrous soil, the strings of fish on thy back; travel from city to city (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1961), 133.