There are many good reasons to keep fish as pets, says veterinarian David Gething, of Creature Comforts (www.creaturecomforts.com.hk), but they should not be relegated to a small tank in the corner of the room.

"Fish are a great first pet for children," Gething says. "And a basic aquarium is cheap to buy and simple

to maintain.

For those new to fish-keeping, there are three general types of aquarium fish: cold-water (goldfish), tropical fish (brightly coloured, ornamental fish that require a heated tank) and marine fish (saltwater fish from tropical reefs).

"I'd recommend a new fish-keeper start with cold-water fish such as goldfish," Gething says. "These are the easiest and require the least equipment."

As skill levels and interest grows, he says, people often move on to more complicated tropical and marine fish.

Gething recommends purchasing fish and equipment from Tung Choi Street, in Mong Kok. Also known as "Fish Street", it is lined with aquarium stores selling fish of all shapes and sizes. Shops can help recommend equipment, but as a guide he suggests a 20-litre aquarium tank, an air pump and a filter. "Avoid very small tanks or those without filtration as the water conditions and tank health can rapidly [deteriorate]. You should also buy some drops to add to tap water to remove any chlorine or impurities."

His next advice is "don't buy the fish on that first visit. It's important to take the tank home and get it set up and working for a few days before adding the fish".

After establishing the tank and allowing it to settle, buy a few goldfish, not too many, or they may overload the tank and pollute the water. It's also fine to add a few aquarium plants, Gething says, but check that they are suitable for cold-water tanks.

Goldfish should be fed once daily with a suitable flake food, just a small pinch. Too much will also spoil the water. He says that every two weeks, roughly 20 per cent of the water in the tank should be removed and replaced with fresh tap water, after adding the chlorine-removal drops. "This helps keep the water fresh and free from contaminants or pollutants."

As the tank becomes more established more fish can be added, but do not overcrowd the tank. As a guide, Gething says a 20-litre tank could hold up to 10 small goldfish.

Goldfish are generally hardy and rarely have any problems, but signs of trouble to watch out for, the vet says, include not eating, damaged fins, cloudy eyes and small white spots or blotches on the body. "Over 90 per cent of problems in a tank are caused by one of the four issues mentioned above: overstocking, overfeeding, not changing water regularly, or poor filtration and aeration. If this doesn't fix the problem, I'd recommend discussing with your vet."

Gething says it is important to get to the root of the problem rather than just replacing fish, "otherwise the problems will unfortunately just recur or get worse".

Keeping tropical fish requires a little more time and care, the vet says, and the fish are more sensitive to changes in water temperature and quality. In addition, a tropical tank will require a heater and possibly specialised lighting, if the tank contains exotic aquarium plants. It is also necessary to monitor water quality and acidity with a test kit.

"When stocking a tropical tank it's important to choose fish species that can be kept together. Tropical fish come in a wide variety of shapes, sizes, temperaments and requirements for water conditions. A good tropical fish tank will have a mixture of fish species, but the different species need to complement each other," Gething says.

An aquarium store can help advise on compatible fish but, as a general guide, he recommends new tropical fish-keepers start with small tropicals such as tetras, guppies, platies and rainbow fish.

Marine fish are another level of complexity again, and often require specialised set-ups and a high level of knowledge. "They are generally not suited for beginners, and I would also remind potential owners that nearly all marine fish and corals are collected from the wild. Coral reefs around the world are under threat and some have suggested that it may be better to leave these beautiful creatures in their natural habitat."

Getting started with fish-keeping is inexpensive and easy, and the hobby can develop as your interest grows, the vet says. "An aquarium can be a beautiful addition to the home and, best of all, watching fish swim is scientifically proven to reduce stress, something we can probably all use." 

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