Newsletter No. 22

CUHK Newsletter No,22 September 1991 day. Instead of feeding them the ‘red insect' fish food most commonly used in Hong Kong, high nutrient fish food was used, as it is less likely to be contaminated. Lettuce, cabbage and turnip buds ground with raw salt were also added as a fibre supplement to provide the carp with some degree of immunity from disease. Small Fry Under the care and attention of Mr. Chan and his colleagues, the new arrivals settled comfortably into their new home. A year later, more new arrivals joined the community, in the form of baby brocaded carp. The population increase would have been greater had not the fish inadvertently consumed their own eggs along with their food. A great deal of effort had to be made in order to establish a successful breeding programme for them. Staff had to maintain a close watch over the fish during the breeding season in March and April. If they suddenly started to leap out of the water during the night, this was a sure sign that eggs would be found in the pond in the morning. Carp usually lay their eggs between seven and eight o'clock in the morning. The female is shadowed by the male, who is therefore ready to fertilize her eggs as soon as they are laid. University staff have to be ready to take action: they remove the eggs from the pond before they can be eaten by the parents, doing so by stirring coconut threads and bark in the water. This attracts the sticky eggs, which can therefore be easily removed from the pond. The fertilized eggs are then transferred to large tanks into which fresh air is continuously pumped throughout the day and night. After a week, tiny pinsized carp emerge from the eggs. To start with, the fry are colourless; it takes another week before they begin to develop colour. Leeches are then fed to the developing fry and three or four weeks later, the small carp are ready to join their parents. The number of carp increased rapidly and it was not long before over- population led to the pond becoming overcrowded. Consequently, over a dozen of them were transferred to the fish pond at the residence of the head of Chung Chi College, which has since become the Chinese Music Archive Building. Later, some were relocated to the garden of the vice-chancellor's residence and the lily pond at Chung Chi College, while others were donated to Ocean Park. Theft The Buildings Office also maintains a small pond by its nursery as a temporary shelter for ‘surplus' carp from the Art Gallery. One night in July 1985 ， more than 20 of the brocaded carp were stolen from this small pond. They were all so beautiful, so chubby. Such excellent colour! Best of the crop! ’ Mr. Chan Wei Sun still speaks with much regret over their loss. However, no one realized in 1985 that a far greater loss was in store for the shoal. Tragedy Struck Although brocaded carp adapt easily to new environments, and can live for up to 45 years, they are very susceptible to a number of diseases. There is also a tendency for blood sucking fish fleas to stick to the carp, exacerbating the spread of disease amongst the carp population. In 1986 tragedy struck, in the form of a plague. Dead carp were found in the pond every day. Their population dwindled until only a vey small number remained. Fighting Diseases One of the problems of treating sick fish is that they are unable to tell their caretakers that they are ill, so it is the responsibility of the staff to detect any diseases in their early stages. Mr. Chan, having learnt from many years of experience, observed that carp in the early stages of illness stop eating and stay at the bottom of the pond, away from the rest of the fish. If the fish are suffering from a really serious disease, their scales will decay and fall off, and their wounds may even bleed. The staff team gradually learned, by trial and error, how to treat the sick carp. They contacted many different authorities on fish, including the Marine Science Laboratory, and adopted some simple but effective methods of treatment. For instance, fleas can be separated from the bodies of the carp with small bamboo sticks. Diseases in their early stages can be treated by adding penicillin to fish food, or soaking the sick carp in dilute saline solution. Instead of receiving medical treatment, 'terminal cases' were often transferred to the lily pond at Chung Chi College to spend their final days in peace and quiet amongst the beauty of the lilies. More often than not though, these patients recovered completely without treatment. This has led Mr. Chan to believe that the lily pond, with its natural abundance of water weeds and microbes, is a far better habitat for the beautiful brocaded carp than the fish pond at the Art Gallery. Return of the Golden Days Notwithstanding disasters natural and human, this fertile species is gradually increasing its numbers again. Last year, after a major ‘clearance’ of the lily pond at Chung Chi College, some 20 carp were transferred there to grow and to reproduce. From 20 the number has grown to over 1,000 this year. Big and small, this new generation of brocaded carp will eventually be sent to various locations on the campus such as the ponds at the vice-chancellor's residence, the Forum, and the Art Gallery. The ‘golden days' of the Art Gallery pond will very soon return. 6