A Beginners’ Guide To Fish Keeping

FISH KEEPING can be divided into four main groups:

  1. Freshwater cold (e.g., goldfish);
  2. Freshwater tropical (e.g., tetras);
  3. Marine cold (some gobies), and
  4. Marine tropical (e.g. clowns).

Within each of these, there are myriads of variations. For the beginner, I would recommend that you start off with a freshwater set-up. Freshwater fish tend to be more tolerant to environmental changes. Because fish swim, live, eat and defecate in the water, the quality of the water becomes very important. Smaller tanks can hold only small volumes of water, and the water quality can fluctuate very quickly with little warning. Larger tanks tend to be more stable (in terms of water quality parameters), and so you are less likely to end up with disasters. So, the best tank size to start with is the largest tank that you can afford to buy.

A starter tank should be at least a standard three-foot. Glass aquarium or plastic? Glass aquariums are heavier, you can get them in larger sizes and they do not scratch as easily. Plastic ones cannot withstand large volumes of water. But, the story does not end there. You cannot just add water and fish like any instant noodle packet directions.

You are creating a real living underwater world. It needs time to simmer, and you need to have a taste every so often before it is ready. The same applies to setting up an aquarium (although, I would advise against tasting the water — it is better to get it tested). The fish tank and stand should be situated on a strong, stable and level floor. A sheet of polystyrene foam should be placed between the aquarium and the stand to absorb any unevenness and to spread the entire weight of the tank more equally. The tank should not be placed in direct sunlight (to prevent excessive algal growth) and not along corridors where it is drafty.

Make sure that you are happy with the location of your tank before filling it because once water and aquarium furniture are added, the tank becomes very heavy and even dangerous to move. Always drain the tank and remove as much aquarium furniture as possible before relocating an aquarium.

Other things you need are listed on the next page:


Once the tank is in place, gravel should be added (if using an under-gravel filter, place the filter plate before adding gravel). Gravel should be from an aquarium shop since those sold in garden shops may leach out harmful chemicals. Gravel should be arranged such that it slopes towards the front. This helps to channel rubbish to the front where you can clean more easily.

You can add aquarium furniture and plants in the tank either before or after adding water. It is usually easier to plant in a dry tank, but you cannot usually see what it will look like. Heavier aquarium furniture like rocks should only be added after the tank is filled with water, to spread the load across the base of the tank more evenly.

Water should be conditioned before adding to the tank. Water needs to be conditioned because the level of chlorine it contains is toxic to fish (even though it does not harm us). To avoid stirring up the gravel, place an ice-cream container in the tank and pour the water into this receptacle. It will absorb most of the force of the water and overflow into the tank in a gentler stream.

Turn on the heater and set to the desired temperature depending on the type of fish. A good starting point is 25 degrees C. Your filtration system should be started, and the bacteria starter added. Never turn on the heater outside of water because it will be damaged. If live plants were planted, you should wait at least two weeks before the first fish is introduced. This will give the plants time to establish themselves. If no plants were planted, it is a good idea to give the tank a week to stabilize.



Now the exciting part; what fish and how many? There are so many to choose from. The best place to seek advice is at a good aquarium shop. A very important piece of advice is not to buy on impulse. Do a thorough research, taking into account their diet, size and their compatibility. The order you introduce them into the tank is also very important. More dominant and slightly aggressive fish should be the last additions. The number of fish should be introduced over a period of at least one month before the final stocking density is reached. This gives time for the good bugs in your filter to adjust to the new load.

When introducing fish into the tank, the bag should be floated horizontally in the aquarium for about 10 minutes (five minutes longer for larger bags) to equalize the temperature. Then open the bag and gradually add tank water to it for the next 15 minutes to double its original volume. This will slowly acclimatize the fish to the new water conditions. Then, turn the bag on its side to allow the fish to swim out on their own. It is a good idea to feed resident fish in the opposite corner of the tank at the time new fish are released. This gives the new fish some time to wander around the tank without getting hassled by curious residents.


The gold standard is to change 25% of the water every week. However, if your filter is rinsed regularly and you do not overfeed, water changes can be done less often (once a month). Water changes should be should be carried out together with a gravel clean. However, if you are using an under-gravel filter, the gravel bed should not be disturbed as frequently.

Your tank should then be re-filled with conditioned water. This water should come from your cold water tap, and not the hot tap (hot water dissolves the heavy metals in the piping that can harm your fish). This water should then be heated using your aquarium heater before adding it into your tank.


Fish should only be fed as much as they will consume within two minutes. Any uneaten food should be removed after such time. A rule-of-thumb is that the size of a fish’s stomach is as big as its eye. This means that fish do not need to be fed too much. More often than not, fish die from overfeeding than underfeeding. Some fish can over-eat and die. Uneaten food will pollute the water and create poor water conditions, and the entire tank of fish will be unduly stressed, predisposing them to disease.

The Fish Vet at www.thefishvet.com.au, and their YouTube channel tinyurl.com/thefishdoctor.

Dr. Richmond Loh DipProjMgt, BSc, BVMS, MPhil (Pathology) Murdoch, MANZCVS (Aquatics & Pathobiology), CertAqV, NATA Sig. is an aquatic veterinarian and veterinary pathologist in Perth, Western Australia.


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