Fishes do smell. This is one of the vital part of the organ that helps the fishes to locate their foods especially those that hunt in milky water or during the dark.
Beside being the only channel where foods are entered, the inner part of the mouth contains the taste sensory. Some fishes have this sensory cells grown around the lips and head to provide acute taste to what they want to hunt. So fishes can taste too.
3) Operculum / Gill Plate
As the name has suggested, it is a protection cover to the gills.
4) Pectoral Fins / Pelvic Fins
Pectoral Fins allow the fishes to stablize. rotate and act like a water-braking system to halt or slow down its speed during swim. Some fishes also use this fins to paddle backwards.
Pelvic Fins allow the fishes to stablize itself and act like a water-braking system.
5) Anal Fin
Anal Fin keeps the fish upright during swimming and also act likes a sub-rudder to help fishes to steer during high speed swim. Some fishes has also developed the Anal Fin as part of its sexual organ.
6) Caudal Peduncle / Caudal Fin (Tail)
Caudal Peduncle is the engine to thrust the fish forward and Caudal Fin is the propeller that releasing that thrust. Caudal Fin also acts as the main rudder during swim.
7) Dorsal Fins (Hard and Soft Fins)
The Hard Dorsal Fin sometimes also known as Spinous Fin. Both Hard and Soft Dorsal Fins help to stabilize the fishes at a upright position. Hard Dorsal Fin is make up of several hard spines which are used as a defensive weapon against predators. During mating or territorial right, some fishes will spread its Hard Dorsal to display supremacy.
Some fishes has developed their Hard Dorsal Fin with venomous spines, so anglers have to handle fishes with care.
Soft Dorsal Fin act like a sub-rudder during high speed swim, similar to Anal Fin.
8) Lateral Line
Lateral Line is one of the vital organ that helps the fishes to detect movement in order to evade predators or locating their preys. This line can be seen running along both sides of the body, starting from the head and runs toward the Caudal Peduncle.
Some fishes has developed even complicated sensory to give acute sensing: examples are Sharks and Gill-fish.