Aquarium is a place to preserve freshwater or seawater aquatic organisms, and also a facility to collect aquatic organisms for exhibition or scientific research.

Historical background

Sumerians are called the earliest fish farmers. They built the pond culture at least 4,500 years ago. The record of fish farming can be traced back to ancient Egypt and Assyria. China people raised edible carp as early as 1000 BC, and they were probably the first people to make achievements in fish farming. Their method of selectively breeding ornamental goldfish was later introduced to Japan; In Japan, the cultivation of ornamental fish has been improved. The ancient Romans raised fish for food and entertainment. They are the earliest known guardians of marine life. They built fish ponds and injected fresh sea water. Although goldfish could be raised in glassware in Britain as early as the middle of17th century, it was not until a century later that people understood the relationship between oxygen and animals and plants that fish culture in fish tanks was established.

By 1850, the reproduction of fish, amphibians and reptiles has greatly helped the study of nature. The word aquarium first appeared in the works of British ornithologist Phillip Goss. His and others' works aroused public interest in aquatic life. The world's first aquarium for exhibition was opened to the public in Regent's Park on 1853. Later, there were aquariums in Berlin, Naples and Paris. Barnum, the founder of the circus, realized the possibility of commercial utilization of live aquatic animals, and opened the first private aquarium for exhibition at the American Museum in new york on 1856. By 1928, there are 45 public or private aquariums in the world. Since then, the development speed has slowed down, and only after the Second World War did several new large aquariums appear.

Now many important cities in the world have public and commercial aquariums. Another type of aquarium is mainly used for scientific research, among which the most famous ones are the Naples Aquarium, the Aquarium of Monaco Oceanographic Institute, the Plymouth Aquarium of Plymouth Marine Life Station in England and the Aquarium of Scripps Oceanographic Institute in Lahora, California. Another kind of aquarium is a temporary aquarium displayed at various world expositions and exhibitions.

Marineland, Florida, USA is the first large-scale marine aquarium, 1938 is open to the public, and it is a private enterprise. It is characterized by the use of giant fish tanks and trained dolphins. Pacific World in palos, verdes, California is similar to the Marine Aquarium in Miami. The special value of this aquarium lies in its giant water tanks, each with a capacity of/kloc-0.0 million gallons, in which all kinds of fish are kept indiscriminately. In a regular aquarium (such as Shedd Aquarium in Chicago), different kinds of fish are separated.

Design and architecture

The earliest container specially designed for aquatic organisms was a rigorous and practical outdoor water tank, which was used by the Romans to preserve and fatten fish for the market. It was not until the18th century that goldfish used for artistic appreciation were introduced to France from the east, and there was a requirement to build a small aquarium. Made into a ceramic cylinder, occasionally with transparent parts. 1850? During the period of 1880, large public aquariums built in many European cities tried to give the audience the illusion of being immersed in the underwater world. In recent years, it tends to emphasize the natural beauty of each species, and tends to form obvious differences between water and viewing places.

Water tanks, regardless of size, from small water tanks that can't hold 1 gallon to giant water tanks that can hold1million gallons of water, should be carefully made; Many substances, especially plastics and adhesives, are not toxic to people, but toxic to animals that breathe in water.

Although polyethylene, polypropylene, Plexiglas and fluorocarbon plastics are generally nontoxic, the safest basic material may be glass. Glass fiber has been widely used. If properly prepared, it is harmless. Adhesives for sealing include epoxy resin, polyvinyl chloride, silicone rubber (except some colored products) and neoprene. Metals are usually not used, especially in seawater, because seawater is very corrosive. However, due to its low toxicity, stainless steel is often used, especially in fresh water equipment.

Small water tanks can all be made of glass, and silicone rubber is not needed as the supporting frame of adhesive. In addition to the largest water tank, the most practical supporting material for various water tanks may be glass fiber, which is light and strong, does not deteriorate, and can be easily processed into any shape. Although wood is widely used, it is easy to rot and be eaten by insects and must be protected. Reinforced concrete, including the mixture specially prepared for use in seawater, is the main supporting material for building large aquariums.

In modern aquariums, water tanks of different sizes and shapes are often put together to avoid the "fish box" appearance common in some older formal aquariums. The stereoscopic scenery behind the water tank creates the illusion of a long distance; The location of the water tank can be natural environment, or filled or coated with glass fiber to simulate all environments. Modern aquariums try to show the natural living environment of all kinds of fish on exhibits.

Polished flat glass, toughened polished flat glass and plexiglass are commonly used light-transmitting materials. Polished flat glass is usually only used in small aquariums, because when its strength weakens, it will break into large pieces. The usual practice is to equip the large water tank with 2? Three layers of tempered glass, even if broken, is limited to one layer of glass. Plexiglass is easy to scratch, but it can be polished again.

The auxiliary equipment of the water tank usually includes filters, air pumps, lamps, immersion heaters controlled by electronic constant temperature or other cooling devices. In an aquarium, the water tanks are usually put together, so there can be filters and temperature control devices for * * *. It may also include a water sterilizer. In large aquariums with various systems, indoor water supply and drainage facilities are sometimes very complicated, involving various automatic control devices and water quality monitoring systems. Glass pipe fittings, such as those used for inflating and circulating water in aquariums, are expensive and fragile, so they are only used when low toxicity is needed. Non-expanded PVC pipes are widely used. Glass fiber pipes and asbestos pipes lined with epoxy resin are sometimes used, but lead pipes and hard rubber pipes have been abandoned. Organisms that cause siltation, such as mussels and barnacles, will grow in pipes that use seawater. If two sets of pipes are used and put into use every other week, the growth of these creatures can be avoided. After the pipeline is dried, a few creatures in the pipeline will die, and when the pipeline is put into use again, these creatures will be washed away.

In terms of toxicity, nonmetallic pumps or pumps lined with plastic are better than metal pumps, but usually stainless steel pumps meet the requirements. When the diameter of pneumatic pump (such as the pump used for fine sand filter of domestic water tank) is large enough, a large amount of water is pumped out.

Usually, the most effective lighting is the incandescent lamp above the front glass. Fluorescent lighting is uniform, but it may be too bright for the four walls of the water tank; Colored lights emphasize natural colors; Mercury lamp promotes the growth of marine plants as soon as possible.

It is of practical value to keep some aquatic plants in the water tank, although the appearance of plants in the water tank may cause complicated situations. Aquatic plants absorb dissolved oxygen and discharge carbon dioxide; Under the influence of strong light, plants will also absorb carbon dioxide and expel oxygen during photosynthesis. In turn, fish waste forms fertilizer or food for plants and is absorbed by plants. As long as a certain intensity of light shines on plants, this effect will be fully exerted. It is generally believed that animals and plants can balance each other in the process of breathing in a water tank, which is usually called a balanced water tank.

Inventory problem

The design of large aquariums must take into account the requirements of various species; Especially because the exhibits in modern aquariums include all kinds of aquatic life; Mammals, birds, reptiles, amphibians, invertebrates and fish. Among many factors that must be considered, including the flow pattern of tourists, the reflection of glass, acoustic effect, and the water clarity, dissolved excrement, temperature, water tank decoration, disease treatment, nutrition and other water tank stocking.

The main requirement for stocking aquatic organisms is water quality. Water sources are not allowed to have pollutants, such as sewage and industrial waste; The gas in the water must be in balance with the atmosphere to ensure that there is enough oxygen in the water; While avoiding supersaturation of nitrogen. In the recycling system, the treatment of water should not only ensure the clarity of water, but also ensure the purification of excreta. Fresh water sources usually need carbon to filter water sources, or chemicals are added to remove chlorine and other additives. Marine life can be stocked in natural seawater or artificial seawater. The advantage of artificial seawater is that it has no pathogenic organisms and pollutants, but it may not be so suitable for some organisms.

There are basically three water supply modes: open, closed and semi-closed. In the open water supply system, the water is discarded after passing through the water tank, and the water quality is close to the natural environment, and toxic metabolic excreta will not be accumulated; However, the cost of temperature control and water pumping is high, and filtration is often needed.

The water in the closed water supply system circulates repeatedly, only changing water regularly. Excrement can't be washed out of the system continuously, so it must be treated. An important problem is that the ammonia in it must be quickly removed or converted, because ammonia is harmful even at very low concentrations. In the water tank, the bacteria that convert ammonia into nitrite mainly live in the filter material. Usually, a sandy slow filter with large surface area is used to ensure the existence of these bacteria in large quantities. Plant growth in water tank, especially in seawater water supply system, usually can't make full use of all nitrate produced by bacteria from nitrite. Although some water tanks rarely change water for many years, they generally need to change water 1? 10%, keep nitrate at a low level. The use of carbon in fresh water and seawater supply systems helps to slow down the accumulation of nitrogen-containing waste. Feces can also cause the acidity of water to increase. Carbonate compounds are usually used to keep the acidity at an optimal level, especially when water is not changed frequently.

Semi-closed water supply system is basically the same as closed system, but it has a fixed relationship with water source. Adding fresh water regularly to control the problem of dissolving waste is lower than that of open water supply in controlling water temperature and pumping water.

There are all kinds of filters, from simple circulation system to automatic recirculation system, equipped with special equipment to monitor various physical and chemical characteristics of water. The water exchange rate of each water tank is very important, and it should not exceed two hours. There should also be a ventilation device with a blower to prevent fish from choking if the water supply is unexpectedly interrupted.

Fish and invertebrates can be kept in a tank that is "balanced" with plants without filtration or ventilation; However, it is extremely difficult to achieve a balance between large animals and plants, even in normal water tanks, especially in seawater tanks.

Freshwater ponds for raising mammals and birds have special problems. They usually need higher filtration speed and greater filtration capacity, because there are a lot of feces piled up in these places. However, animals that breathe air are not very sensitive to water quality; Therefore, chemical treatments, such as chlorination, can kill fish, but they can be used to control bacteria and improve the transparency of inflow. Artificial seawater is relatively simple; Artificial seawater containing 2% sodium chloride can feed whales and dolphins. Seals and sea lions have been kept in fresh water, but the incidence of eye diseases will increase, which is caused by the infiltration of fresh water into eye tissues.