topminnow

Noun

• freshwater fish of Central America having a long swordlike tail; popular aquarium fish

• small usually brightly-colored viviparous surface-feeding fishes of fresh or brackish warm waters; often used in mosquito control

Related words

• Synonyms: 
  swordtail , helleri , Xyphophorus helleri , poeciliid fish , poeciliid , live-bearer