Suckerfish or sucker may refer to:

• the remoras (family Echeneidae): ray-finned fishes that use suction to hold onto larger marine animals
• the family Catostomidae (suckers): freshwater fish found mostly in North America
• the species Hypostomus plecostomus (the suckermouth catfish), or other members of family Loricariidae
• Chinese sucker fish (Beaufortia kweichowensis): a hillstream loach species native to the riverine fauna of China