Tilapia: The body side is higher, the dorsal fin has many 10 fins, the caudal fin is flat or round, and there are many longitudinal stripes on the body side and caudal fin.

Bream: It is tall, flat on its side, with a diamond-shaped body, with a body length of about 50 cm, which is 2.2-2.8 times its height. Its back is blue-gray, its sides are silver-gray, its abdomen is silver-white, its side scales are gray-white at the base and its edges are gray-black, forming gray-white stripes.

I. Natural classification

1. Tilapia belongs to Chordata, Vertebrate, Actinidia, Actinidia, Perciformes, Arowana, and Silurus.

2. The bream belongs to Chordata, Vertebrate, Bone Fish, Kiwifruit, Cypriniformes and Cyprinidae.

Second, the appearance characteristics

1. Tilapia belongs to small and medium-sized fish, and its shape and individual size are similar to those of crucian carp. Its side is higher, its dorsal fin has more than 10 fins, its caudal fin is flat or round, and there are many longitudinal reticular markings on its side and above the caudal fin.

2. Megalobrama amblycephala is a medium-sized fish, with a rhombic body, a flat body height and a body length of about 50cm, which is 2.2-2.8 times the body height. The head is small and the back of the head bulges sharply. The height of dorsal fin is obviously higher than the head length, and it has hard spines. The pectoral fin just reaches the root of the pelvic fin, and the pelvic fin only extends to the anus. The caudal fin is deeply bifurcated, and the lower leaf is longer than the upper leaf. The back of the body is bluish gray, the sides are silvery gray, the abdomen is silvery white, and the fins are grayish black.

Third, the living environment.

1. Tilapia is a tropical fish, native to Africa. It can survive in seawater and fresh water. At present, it is mainly cultivated in Guangdong, Guangxi, Hainan and other provinces with high temperature, mainly inhabiting the middle and lower layers of water, but it will change with the water temperature or the size of fish.

2. Megalobrama amblycephala is an endemic fish in China, mainly distributed in medium-sized lakes attached to the middle and lower reaches of the Yangtze River, and is one of the main freshwater cultured fish in China, mainly inhabiting the waters with more muddy sediments and submerged plants.

Fourth, eating habits.

1. Tilapia is an omnivorous fish, which mainly feeds on plant food.

2. Megalobrama amblycephala is a herbivorous fish, which mainly feeds on aquatic vascular plants such as Sophora alopecuroides, black algae, POTAMOGETON POTAMOGETON, and can also eat lake bottom plant debris and a small amount of zooplankton.