Goldfish, once the top freshwater pet fish of choice, are still as popular as ever, according to veterinarian Dr James Blanshard. "They are attractive, potentially easy to keep, and do not occupy lots of space," he says. Other favoured options include cichlids of all varieties, including the flowerhorn cichlid, arowana and koi carp.
When keeping fish as pets, one of the most important health factors is water quality.
"Fish live, eat, defecate and respire in the same water, and that environment needs to be maintained to a high level. Temperature, oxygen levels, waste-product levels, pH, all need to be kept in close check. It is often when water quality falls out with the ranges of tolerance that fish die," Blanshard says.
If adding a new fish to a collection, Blanshard has this advice: "Don't add it to your existing collection immediately, but quarantine it for two weeks to monitor for signs of ill health and make sure that you are keeping appropriate species together. Some fish will attack and eat others."
Another important factor is that fish have a wide range of individual dietary needs, so researching the appropriate diet for fish types is necessary.
Like all animal species, fish can develop health problems, although the vet says he does not see a lot of goldfish. "There are many goldfish keepers in Hong Kong but, owing to the availability of home remedies from most fish shops, a lot of keepers elect to treat goldfish themselves at home. Also, cost is an issue. With goldfish being so cheap to buy, in many cases, owners are reluctant to spend money on diagnostic tests and treatments required."
He says when it comes to more expensive fish, owners are more willing to take them to a vet when a health issue arises.
Common problems include buoyancy issues, such as sinking, swimming at an abnormal angle, floating to the surface, and bloated or swollen fish, parasitic diseases, skin diseases and tumours.
Blanshard says fish can be rewarding pets, but it is important not to rush into keeping them. "Do your research. Set up your tank long before you buy the fish and get the tank established. By this I mean allow the water parameters to settle down and a biological filter to become established," he says.
"This biological filter will keep levels of waste products under control when you add the fish. Have the tanks running for a couple of weeks before adding fish. When you do, add a hardy species first before adding a more delicate, sensitive variety."
He also advises owners not to overfeed, as this is a common contributor to poor water quality, due to the uneaten food rotting in the water. Owners should also avoid overstocking, as too many fish in a tank will lead to health problems.
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