1. Mouth
Position
And feed habit

2. The position of a fish’s mouth can tell you a lot about the feeding habits, living style and type of behavior it exhibits. A fishes mouth type may be broadly divided into three categories,  midwater ( Terminal),  Surface feeders (Superior) and bottom-feeders (inferior).

3. Superior
The superior mouth is oriented upwards and the lower jaw is longer than the upper jaw.This kind of fish has an upturned, scoop-like mouth which is designed to feed on prey that swims above the fish, or perhaps on the surface of the ocean or lake, such as insects or plankton. Surface feeding fish usually have an undershot or upturned (superior) mouth for feeding on insects or floating prey. However a superior mouth doesn’t automatically signify a surface swimming fish; fish with this mouth position feed on food that is above them and are either a predator or a strainer.

4. Culter alburnus Basilewsky
翘嘴鲌
Archerfish
射水鱼
Ilisha elongata 鳓鱼

5. Terminal
Terminal mouths are located in the middle of the head and point forward. Fish with a terminal mouth position have a mouth in the middle, or center of their head.  These fish either chase their food or feed on what is ahead of them.  The terminal mouth position is considered the “normal” position, and most fish inhabiting the middle levels of the oceans or lakes possess terminal mouths.

6. Tenualosa reevesii，Hilsa reevesi鲥鱼
Siniperca chuatsi 鳜
Konosirus punctatus 斑鰶
Black Ruby Barb 钻石黑三间

7. Inferior
Also called a sub-terminal or ventral mouth, the inferior mouth is turned downward. The lower jaw is shorter than the upper jaw, and the jaw will often be protrusible.Bottom feeding fish generally have an underslung or inferior mouths. ventrally-oriented mouths or mouths located under the fishes head that are adapted for scavenging or grazing on algae, invertebrates or mollusks, and are usually seen in fish such as the catfish or flatfish like halibut or plaice.

8. Pelteobagrus fulvidraco 黄颡鱼
Sinilabeo rendahli 华鲮
Acipenser sinensis 中华鲟

9.
/fish-identification-guide-fish-anatomy-part-ii/

10. 谢谢观赏