1) Aquarium fish 2) Cyprinodont 3) Fish 4) Helleri 5) Popular aquarium fish 6) Saber fish 7) Topminnow 8) Xyphophorus helleri Found on https://www.crosswordclues.com/clue/swordtail
(Xiphophorus helleri), popular tropical fish of the live-bearer (q.v.) family Poeciliidae (order Atheriniformes). The swordtail is an elongated ... [3 related articles] Found on http://www.britannica.com/eb/a-z/s/197
Sword'tail` noun (Zoology) (a) The limulus. (b) Any hemipterous insect of the genus Uroxiphus , found upon forest trees. Found on http://www.encyclo.co.uk/webster/S/261
any of several small, brightly colored, viviparous, freshwater fishes of the genus Xiphophorus, native to Central America, having the lower part of the caudal fin elongated into a swordlike structure: often kept in aquariums. Found on https://www.infoplease.com/dictionary/swordtail