in recent years, it has become a common practice to raise tropical fish in tropical and subtropical areas. Most of the so-called tropical fish refer to those tropical freshwater fish that dance in the water and have bright colors. The first country in the world to feed tropical fish was France. In 1868, Capone introduced tropical freshwater fish to Paris for breeding. The English name of the fish is ParadiseFish (which means fish in heaven or fish in heaven), and the scientific name is Macropodisopercularis. It is actually a wild betta fish in South China, also known as China Betta. This is the earliest tropical freshwater fish in the world as an artificial breeding ornamental. Tropical fish are charming because of their vigorous posture and colorful colors.

There are many kinds of tropical fish, generally including:

Cetaceae: Cetaceae have strong adaptability to the environment and can live and reproduce in hard water. And can withstand the low temperature of 16-18 degrees. The fish doctors of this family reproduce their offspring in ovoviviparous way. Larvae are easy to survive, but most parent fish have larval habits and need to be propagated by isolation method. This is the easiest family of tropical fish to raise and breed, and it is the entry fish for the first time to raise tropical fish.

CYPRINIDAE: CYPRINIDAE fish are mainly distributed in Southeast Asia and Africa. Fish of this family produce sticky eggs, which need aquatic plants and other attachments to attach eggs. Parent fish do not love their children, but have the habit of swallowing eggs. Therefore, after spawning and fertilization, male and female parent fish should be fished out.

Cyprinidae: It is the most diverse family of tropical fish. Most species are petite, beautiful and mild-natured, and only a few are carnivorous large and fierce fish. All belong to oviparous fish. Eggs are sticky, so fertilized eggs need to be attached to aquatic plants and other attachments to hatch.

Lycopodidae: fish are large in size and have the habit of caring for and protecting their offspring. Some varieties have to choose their own spouses and have the habit of defending their territory. Most species are required to lay eggs on smooth stones or pottery pieces. Likes to eat live bait of animals with large individuals.

The fishes of the family Percidae have an auxiliary respiratory organ-pleated gills, which can swim to the surface to swallow the oxygen in the air when the water is short of oxygen, so they generally do not suffocate and die because of the lack of oxygen in the water. The requirements for water quality are not harsh. During the breeding period, the parent fish is dressed in the color of marriage, which is not usually available, especially for the male fish. Most of the fishes in this family are oviparous and fertilized in vitro, and the males have the characteristics of foaming and nesting and protecting young. Fertilized eggs and fry are very small, so the open bait needs miniature live bait.

tropical fish are usually born in tropical waters. However, in the waters close to the tropics and the north and south subtropics at the junction with them, all the fish species with ornamental value are also classified as tropical fish. Therefore, the distribution of tropical fish should also include some subtropical areas.

Tropical fish, in fact, is a part of ornamental fish unique to tropical and subtropical areas, which is called tropical fish by fish lovers to distinguish it from other ornamental fish (such as goldfish and koi fish). Native tropical fish live in fresh water areas such as rivers, streams and lakes. The producing areas of tropical fish are mainly distributed in Southeast Asia, Central America, South America and Africa. Among them, the Amazon River system in South America produces the most kinds and the most beautiful forms, such as the angelfish, which is known as the queen of tropical fish, and the expensive arowana, which was born there. In Malaysia, Indonesia, Sri Lanka, Thailand, Myanmar and other countries, there are also many kinds of tropical fish, such as small and gorgeous lilies and naive kissing fish. In the south of Guangdong, Guangxi, Yunnan and other provinces in China, there are also beautiful ornamental fish, such as Baiyun snakehead in Guangzhou, bluestar fish in Xishuangbanna, and Bodhisattva fish in Nanning.

in China, the history of raising tropical fish is not too long. It was introduced to China from abroad in the 193s, and it first appeared in Shanghai and Guangzhou, and then gradually spread to large, medium and small coastal cities, with fewer species raised than those abroad. With the continuous development of China's economy, the gradual improvement of people's living standards and the diversification of people's living needs, many cities have established ornamental fish markets. For example, there are only three large markets like flowers, birds, fish and insects in Nanning), which shows that people have a strong interest in raising and watching tropical fish.

There are various classifications of aquatic plants. The most basic classification is to divide them into the following five categories according to the differences of their original growth forms:

(1) Submerged plants: plants whose whole plant grows in water, for example, snapdragon.

(2) Floating-leaf plants: plants with roots at the bottom of the water and leaves floating on the water, such as lotus.

(3) Hydrophilic plants: plants with roots at the bottom of the water, and some stems and leaves can grow out of the water, for example, elephant grass.

(4) floating plants: plants that do not take root at the bottom of the water, but their stems and leaves float on the water, and their roots hang down in the water, for example, daffodils.

(5) Intermediate plants: plants that can be born in water without fixed roots, stems and leaves, such as moss.

another classification of aquatic plants is to simply divide them into two categories according to the shape of plants: (1) aquatic plants with stems: plants with obvious stem organs, and their stems have two growth forms, the most common ones are vertical growth, such as green feathers (Figure 3-4) and LYSIMACHIA. If the water is deep enough, some stems can grow very high, even when the plants reach the water surface. The other is creeping growth occurring transversely on the surface of bottom sand, such as Iron Crown (Figure 3-5) and lotus root. (2) Stemless aquatic plants: All aquatic plants that do not belong to the species of stem aquatic plants can be classified as stemless aquatic plants. In fact, there are many stemless aquatic plants that still have stem organs, but their stems are very short (such as crown grass and pepper grass), or blocky (called tubers, such as netted grass) or spherical (called bulbs, such as the heads of weeds), and they grow in bottom sand and are not easy to be found.

if the water plants are distinguished by their colors, they can be divided into two categories: green water plants and red water plants. Although this classification is not rigorous, it is very popular. Because the color of some aquatic plants is easily influenced by the water environment, it changes from green to red, or the same aquatic plant has both red and green colors at the same time. In this case, it is obviously difficult to strictly distinguish between green aquatic plants and red aquatic plants. However, it is still customary to cultivate all or part of the plants of aquatic plants in aquarium, which can be regarded as red aquatic plants. If the green appearance is maintained from beginning to end, it is called green water grass.