Any of more than 30,000 species of predominantly cold-blooded vertebrates found worldwide in fresh and salt water. Living species range from the primitive lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Species range in length from 0.4 in. (10 mm) to more than 60 ft (20 m). The body is generally tapered at both ends. Britanica Encyclopedia.
Other meanings.
FISH Fluorescence In Situ Hybridization (genetics test)
***** FISH Federazione Italiana per il Superamento dell Handicap
**** FISH First In Still Here
*** FISH Friends in Service Helping
*** FISH Friends of the Issaquah Salmon Hatchery
*** FISH Fighting in Someone's House (NATO/British Army)
*** FISH Fresh Ideas Start Here
*** FISH Forensic Information System for Handwriting ...more