any member of the crustacean suborder Euphausiacea or of the genus Euphausia within that suborder. The name is sometimes also used to refer to Euphausia superba, a single species. The Euphausiacea are shrimplike marine animals that are pelagic in habit (i.e., they live in the open sea). They range in size from 8 to 60 mm (about 1/4 to 2 inches). Eighty-two species have been described. Most have bioluminescent organs (photophores) on the lower side, making them visible at night. They are of great importance in certain regions of the sea as food for various fishes, birds, and whales, particularly blue whales and finback whales. Krill occur in vast swarms that may gather near the ocean surface or at depths greater than 2,000 m (about 6,600 feet)., läbipaistva või punase kehaga vähkide selts; u 90 liiki. Hiilgevähilised on kehalt krevetisarnased, 0,7-9,6 cm pikad; nende silmavarrekestel, osal rindmikujalgadel ja tagakehalülidel on helenduselundid (fotofoorid, ). Toituvad pms sestonist ja arenevad keeruka moondega. Rohkesti, suurte parvedena on neid avamereplanktonis, nad on tähtsad eriti kiusvaalaliste, peale selle ka heeringaliste jm kalade toiduna; sobivad ka inimtoiduks. Hulgaliselt leidub hiilgevähilisi Antarktika meredes, arvukaim liik on tavaline hiilgevähk ehk nn krill (Euphausia superba).