Looking after your Fish


Where you place your aquarium is very important, this can have an impact on the health of your fish.

BEFORE you buy, check that you have a suitable place for your aquarium. Choose a position away from sources of heat (including sunlight), draughts and sudden movement (near doorways). Also, avoid places near a hi-fi, television or other domestic appliances as vibrations upset fish.

Don’t forget, your tank will need to be placed near an electrical socket.

  1. Firstly, place gravel into the bottom of the aquarium, rinse it thoroughly before use.
  2. Position any rocks and ornaments securely into the gravel.
  3. Fit your filter, heating and lighting and any aeration equipment.
  4. Add tap water, provided that you have treated it with a conditioner to remove harmful chlorine disinfectants. To avoid disturbing the gravel when adding water place a plate at the bottom of the fish tank and slowly pour the water on to the plate.
  5. Start the filter, then leave the aquarium to settle for at least three days with all systems running before adding any fish. This allows the water to stabilise and ensures a safe environment for your fish.


A water temperature of 24-26°C is standard for a tropical aquarium. This temperature is regulated by a themostat in the heater. A thermometer placed inside the tank will indicate whether the water temperature is fluctuating.

Aquatic plants help to keep aquarium water clear and also provide a place for fish to shelter. The bigger the tank the better as a large volume of water has a more stable temperature and any pollution is diluted.

Water Quality

Test your water to ensure it is suitable for the addition of fish. The most important things to test for are Ammonia, Nitrite and pH level. If the water has high levels of Ammonia or Nitrite then this could be fatal to the fish and increase the risk of them catching diseases.

Ammonia, Nitrite and pH

Ammonia and nitrite come from fish waste and can be fatal if allowed to build up in your aquarium. You cannot see them so your water may look clean but could in fact be toxic for fish to live in. The best way to tell if you have ammonia or nitrite is to test your water. Simple test kits can be purchased from Squire’s or any good aquatic retailer.

The filter will break waste (ammonia and nitrite) down using a beneficial bacteria which will colonise the foam part of your filter naturally (some filters come with a special ceramic media for the bacteria to live in), these bacteria can take up to six to eight weeks to colonise.

If you do get ammonia or nitrite levels that are too high then partial water changes can be used to dilute levels back to zero. You must never buy new fish if you have any ammonia or nitrite.

You can purchase live beneficial bacteria to put in your aquarium to speed the maturation process. This is generally a safer way to mature a tank. DO NOT clean your filter foams under a tap as tap water has chlorine in it that kills bacteria.

A pH test is for measuring the water’s acidity/alkalinity. A pH scale runs from 0 (very acidic) to 14 (very alkaline). As a general guide pH7 is ideal for the majority of fish, but you must check before you buy.

PLEASE NOTE Water quality is most likely to change when you have introduced fish into the tank. It is recommended that you test the water periodically, especially when you have added any livestock.

How many fish?

It is very important not to overstock your aquarium. Introduce fish gradually over a number of weeks. When buying your first fish ask a member of staff for advice on suitable fish for your aquarium.

As a general rule of thumb you can put 1cm of fish to 2 litres of water. This is a guide to maximum stocking levels based on fully grown fish. Don’t forget to account for growth when buying fish. Depending on the size of the aquarium, buy one or two small fish to start off with and wait a couple of weeks before adding more.

When you bring your fish home open the top of the plastic bag and leave them floating in the bag in the tank with the aquarium light off for about 20 minutes so that the water temperature in the bag reaches the same as the water in the tank.

  • During this time add tank water to the bag by dipping the bag periodically into the tank. Then carefully net the fish into the tank.
  • Do not let any of the water from the bag into the tank as this may pollute the tank water.
  • Leave your fish to settle in and wait an hour before putting the light back on.
  • Wait until the following morning before feeding.


Maintaining your aquarium and keeping its water fresh and clean is essential for the health of your fish. Always ensure you unplug all electrical equipment before you begin the maintenance of your aquarium.

Every one to two weeks (depending on the stocking level in the tank) siphon out a third of the tank water and replace with fresh water. Do not use water straight from the tap, fill a bucket then add a de-chlorinator and let it stand overnight until it has reached room temperature. For tropical fish you will need to mix hot and cold water to reach the optimum temperature.

Pumps will also need some maintenance, normally the filter media will need replacing periodically. You should replace foam filter media once it loses its shape. If you have carbon in the filter then this will need to be replaced on a monthly basis. The filter parts should be rinsed on a weekly basis. Make sure you rinse these in used tank water (not tap water).

Remove any algae from the glass using an aquarium scraper. If too much light stimulates algae growth it may be helpful to move the aquarium into a shadier spot. Alternatively reduce the time the light is on. Six to eight hours is normal. Use a gravel cleaner to remove any debris build up at the bottom of the tank. Never clean the tank or its ornaments with general household cleaning products as they may poison your fish. Also, do not clean the exterior of the tank with glass cleaner as this could pollute the water. Do not use polish or insect sprays around the aquarium.


Young, growing fish can be fed twice a day. Feed fully grown fish once a day. Generally only give your fish as much as the fish will eat in two minutes. Flaked fish food is fine, buy a brand that offers complete balanced nutrition. Fish also like finely shredded greens such as lettuce or spinach. Live food such as water fleas or blood worms will give the fish a more varied and balanced diet.

Algae eating catfish such as Plecos need algae wafers and greens. The algae growing on the glass is not enough to sustain them, particularly larger specimens.

It is important not to over feed fish as any food left over will rot and poison the water affecting the fish, or even worse, killing them. In fact, too little food is better than too much.


Providing a clean, hygienic environment for your fish is the best way to help keep them healthy. Many diseases can be prevented by maintaining good water conditions. Fish can get stressed when left in poor water which in turn can lower their immune system making them susceptible to disease.

The following are the most common problems that can affect your fish whether coldwater or tropical, but if you have any doubts about the health of your fish seek professional advice.

Fungus: This can be caused by skin damage which has become infected with white or grey cotton-wool like growths. Treat with an anti-fungal treatment.

White spot: Fish can develop small round white spots all over (usually starting at the fins). This is a fast-spreading parasite. Affected fish may also have rapid gill movement. Treat using an anti-white spot treatment taking care to ensure treatment is correct for the type of fish.

Fin/Tail/Mouth Rot: The fish will be lethargic and not move around the tank much. Ragged fins and/or tail will appear to be rotting away. It can also affect the mouth with cotton wool-like growths. Use a treatment that tackles both bacterial and fungal infections.

Dropsy (protruding scales): Fish scales protruding like a pine cone, are caused by an internal bacterial infection. Treat with an anti-bacterial treatment.

Velvet disease: Clumps of fine gold spots are a skin parasite which can be irritating and itchy to the fish. Treat with an anti- parasite remedy.

Slime disease: A fish’s response to skin parasites. Cloudy grey mucus covers the body. Treat with an anti-parasite treatment.

You will need…

  • Tank
  • Filter
  • Heater (tropical fish only)
  • Thermometer (tropical fish only)
  • Air pump (optional)
  • Lighting Gravel
  • Plants
  • Aquarium scraper
  • Net
  • Gravel cleaner
  • Beneficial bacterial agent (for starting the filter)
  • Food
  • De-chlorinator
  • Water test kit (Ammonia, Nitrite and pH)
  • Ornaments
  • Two buckets


Fish sizes are estimated and may vary slightly.

Our fish carry a 48 hour guarantee. Damaged fish or claims for losses must be reported within 48 hours. After this period conditions are completely beyond our control.

Credit is only given at our discretion after producing a water sample to ensure there is no problem with the water quality . This sample must be provided separately from any dead fish as this will affect the result.

Proof of purchase and the fish will be required. This does not affect your statutory rights.

Whilst every effort has been made to ensure the contents of this web page are correct, Squire’s cannot be held responsible for the result of action taken without the advice of a professional veterinarian.