rainbowfish

noun (plural same or rainbowfishes)

• any of a number of small brightly coloured fish of warm waters, in particular:

  • an Australian freshwater fish (genus Melanotaenia, family Melanotaenidae). (Celebes rainbowfish) a freshwater fish native to Sulawesi and popular in aquaria (Telmatherina ladigesi, family Atherinidae).