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Setting up your Aquarium

This is a step by step guide to setting up an aquarium and by following these simple instructions you can create an ideal habitat for your new fish.

Choosing your fish

There are plenty of tropical and coldwater fish to choose from but it is important that you make informed choices; some fish are not very sociable and will fight, whilst others prefer to live in shoals of their own kind and should not be kept in isolation. When buying your first fish be sure to ask the store team what they would recommend for a new aquarium to ensure you choose the most suitable fish and plan the best community.

Taking them home

When we sell fish we pack them carefully for the journey to their new home, firstly in a plastic bag and then a brown paper bag as keeping them in the dark reduces stress whilst being transported. They should not be kept in the bag for longer than 1-2 hours. When transporting your fish, take care not to allow them to get too hot or too cold as this can also cause stress. When you get them home, turn off your aquarium light and float the bag in your tank for about twenty minutes, allowing the water temperature to equalize, then add some of your aquarium water to the bag and wait a further 10 minutes before transferring the fish into the aquarium with a net. Throw the old water away and do not mix it with the water in your tank.

The fish may be nervous and hide for a period of time, so leave the aquarium light off and let them settle down for a few hours before feeding them.

We strongly recommend that any tank over 30L requires the matching/applicable stand. You may find some manufacturers’ warranties are only valid if your tank is displayed with the appropriate stand.

Feeding your fish

There are a number of fish foods available in flake or pellet form which provide a perfectly balanced diet with all the nutrients your fish require to stay healthy. We also stock frozen food which is nutritious and provides essential variety in your fish’s diet.

Flaked food is suitable for all kinds of fish, although there are many types of specialist foods appropriate for fish that feed in different ways:

  • Surface feeders will readily take flakes and floating pellets.
  • Mid water feeders like granular or slow sinking foods.
  • Bottom feeders should be offered quick sinking foods or tablets.

Feed your fish once a day, offering just enough food so that it is eaten within 2 minutes. Start with a small amount and adjust accordingly. Over-feeding will pollute the water, so ensure any excess food is removed from the tank after feeding.

Maintaining a healthy aquarium

Maintaining the water quality is the most important factor in keeping fish healthy. Regular water changes are vital for keeping your fish healthy (see the water quality section of this leaflet).

New fish are more susceptible to disease, due to the stress of being moved. New fish should therefore be observed very carefully for several days after they are introduced. It is vital for your fish that you maintain a healthy aquatic environment and although many water problems are not visible to the naked eye, the effects on your fish often are. If you observe any changes in behaviour or unusual spots or markings on your fish, they may have contracted an illness and will require treatment to recover. Treatment may range from a substantial water change to a chemical treatment, but many diseases, if addressed early, are curable.

Firstly, you need to consider where to put your tank, as once it is full of water it will be very difficult to move. Your aquarium should be positioned near a mains power supply, away from draughts and direct sunlight to avoid the growth of algae, and out of reach of small children or pets. We recommend you use a specially made aquarium stand or cabinet to hold the tank level or hairline cracks may occur. Use aquarium foam or polystyrene pads to cushion the tank if it does not have raised glass on the bottom and place your tank away from electrical equipment. Secondly, you need to ensure you have the correct equipment. Use this checklist to make sure you are fully prepared:


Internal, external.


Essential if you want to keep tropical fish.

Air Pump

Good for both oxygenation and running air lines or ornaments.


Important for creating a natural day and night environment for your fish and essential for live plants.


Provides a natural environment for your fish and a good rooting base for live plants.


Live or artificial, they help to create a natural environment for your fish. Live plants also provide an important alternative food source for many types of fish.


Aside from simple decoration, ornaments provide hiding places and shelter for fish.

Water Conditioner

An essential item when setting up a tank. Tap water is treated with chemicals which make it safe for us to drink but toxic to fish. A water conditioner or de-chlorinator removes the harmful chemicals.

Water test Kit

Essential for you to monitor the chemical levels in your water before and after adding fish.

Filter boost

Promotes the growth of beneficial bacteria in your filter.


Once you have all the necessary equipment you can set up your aquarium following these basic steps:

1. Wash out your new tank and place it in its intended position. Make sure there are no cracks or damage to the tank.

2. Wash the gravel in cool, clean water. Do not use soap or detergents.

3. Cover the bottom of the tank with gravel to a depth of 5cm at the rear sloping to 3cm at the front. This ensures any waste will accumulate at the front where it can be easily removed.

4. Fit your heating, lighting, aeration and filtration equipment following the manufacturer’s instructions carefully. Do not plug the equipment in yet.

5. Half fill your tank with cold water without disturbing the gravel bed. One method is to lay a piece of polythene, or plastic bag, on the gravel and place a bowl on top. Pour the water into the bowl so that it flows over the side onto the polythene.

6. Wash your plants and decorations thoroughly in clean water and then place them in the tank. Arrange your taller plants at the rear of the tank with the smaller ones at the front to create more depth.

7. Fill the tank to within 2-3cm of the top and add the water conditioner.

8. Plug in and switch on the air pump and filter. Wait 20-30 minutes then switch on the heater.

9. It is important to wait for at least 3 days with all systems running before adding any fish. Initially the water may appear a little cloudy but it will clear.

Water Quality

pH measures the water’s acidity/alkalinity. The pH scale runs from 0 (very acidic) to 14 (very alkaline) and pH7 is an ideal level for the majority of fish. Some fish do prefer different pH levels so make sure you check before you buy.

A temperature of 24-26 degrees is standard for a tropical aquarium and is regulated by a thermostat in the heater. A thermometer should be visible in the tank to ensure the temperature does not fluctuate. Ammonia and nitrite levels should be regulated and although they both occur naturally from fish waste, bacteria living inside your filter convert these dangerous chemicals into nitrate which is less harmful. Regular water changes should keep these levels close to zero. However, bacteria takes time to build up and new tanks are particularly susceptible to high levels of dangerous chemicals. A filter boost can be added to promote the growth of bacteria and speed up this process.

To maintain ideal water conditions and prevent the build up of dangerous chemicals in new aquariums, perform water changes at least once a week by removing 20% of the tank’s volume and replacing it with clean (dechlorinated) water. You can reduce the frequency of water changes to once fortnightly when the chemical levels seem to have settled. You will need to rinse the filter media on a regular basis to remove any large sediment and clear the impellor inside the filter from sludge, but in both cases you must ensure you rinse with water from your tank and not from the tap.

If you have any questions about water quality or tank maintenance then your store team will be happy to help.

Introducing fish

It is important to introduce fish gradually over a number of weeks and not to overstock your aquarium. Your filter will need time to adjust to the increase of ammonia in the water - if stocked too quickly the filter will not be able to control the levels of waste produced and the water will quickly become toxic, so only add a few fish at a time. It can be beneficial over this period to use an ammonia remover. Maintain regular water changes throughout the stocking period to keep control of rising ammonia levels.

We use general guidelines to determine how many fish are suitable for any one aquarium. Tanks are different shapes and sizes, so there is no exact rule, but we use the following ‘size versus volume’ rule as a guide:

Coldwater fish: 0.5cm of fish per litre of water
Tropical fish: 1cm of fish per litre of water

Remember that this is a guide to maximum stocking levels, based on the size of fully grown fish. Always account for growth when buying your fish.

Shopping list for your Aquarium

  • Filter
  • Heater for Tropical Tanks
  • Air pump
  • Lighting
  • Gravel
  • Plants
  • Ornaments
  • Water conditioner
  • Water test kit
  • Filter boost
  • Fish Net
  • Cleaning Pad
  • Siphon

Maintaining your Marine Aquarium

When maintaining your aquarium, little and often is the best practice. Your maintenance schedule will depend on the type of aquarium you have and also what species of fish and corals you have living in it, but as a general rule you should aim for the following:

  • Check pumps and filters are working correctly.
  • Feed twice a day as a minimum with dried and frozen food.
  • Check the salt level and adjust as needed.
  • Clean algae from the glass.
  • Gently rake the sand over.
  • Test the water for pH, Ammonia, Nitrite and Nitrate. You may also need to perform other water tests depending on the type of aquarium you have, such as Calcium levels in a living coral aquarium.
  • Empty and clean protein skimmer collection cups.
  • Carry out a water change of between 10% and 30% of the tank’s volume.
  • Clean filter media and replace chemical and carbon media as recommended by manufacturer.

Converting a Tropical Freshwater Aquarium to Marine

Many tropical freshwater aquariums can easily be converted to house marine fish and corals, and equipment such as heaters and filters can be re-used. Lighting can be upgraded to marine strength tubes and additional filters, water pumps and a protein skimmer added.

You will need the following equipment to convert to a marine aquarium:

Protein Skimmer

Essential for a marine aquarium to help create a stable environment.

Addition Water Pump(s)

Needed to re-create the strong currents found on a coral reef, one or more pumps may be needed, depending on the size of your fish tank.


Depending on which filter you already have, a second filter may be needed, with external filters recommended.

Upgraded Lighting

Marine strength light tubes or LEDs are required and are available in sizes to suit most aquariums.

Coral Sand

For the base of the aquarium.

Living Rock

To build the coral reef structure and help establish the aquarium.

Marine Test Kits

To monitor the water conditions.

Hydrometer or Refractometer

To monitor the salt levels in the water

This leaflet is designed to give you a basic introduction to marine fish keeping, should you have any further questions or require a more in depth explanation, our colleagues in our aquatic centres are more than willing to advise. They are all fish keepers and have a great deal of experience, which they are more than happy to share with you and assist you as you start out in the fascinating world of marine fish keeping.

Shopping list for your marine Aquarium

  • Aquarium
  • Filter
  • Protein Skimmer
  • Water Pumps
  • Heater
  • Lights
  • Sand
  • Living Rock
  • Water Test Kit
  • Salt Level Test
  • Fish Net
  • Cleaning Pad

Common Fish Diseases

Prevention is better than cure

Prevention is better than cure and many diseases can be avoided by maintaining good water conditions. This is because fish become stressed in poor water which can lower their immune system leaving them susceptible to diseases. The most effective way to keep your fish in good quality water is to carry out partial water changes and test your water weekly. This will help you to maintain a disease free, healthy environment for your fish.

Healthy water = Healthy fish

Below is a list of the most common diseases that can affect your fish, whether they are coldwater or tropical.


Often seen as white or grey fluffy, cotton wool like patches on the fish’s body or fins. Very common in livebearers, fancy goldfish and gouramis.


Easily treated with an anti-fungus treatment. Aquarium tonic salt is also of great benefit when treating fungus, and can be used together with some medications. However always check the instructions before using together.

White Spot

Small, round white spots all over the fish, although usually first seen on the fins. Affected fish will have rapid gill movement and will often flick or rub against rocks and ornaments as they try to remove the spots.

White spot is a parasite and the white spots are actually its egg sacks. Even if the white spots have gone, the parasites could still be in the water.


Choose an anti-white spot treatment, follow the instructions closely ensuring the treatment is correct for the type of fish. Also ensure they are treated for the correct length of time to clear all parasites in the water. Aquarium tonic salt is also of great benefit when treating white spot, and can be used together with some medications, although always check the instructions before using together.

Fin/tail/mouth rot

Frayed, damaged and decaying fins and/or tail, which appear to be rotting away. If the mouth is affected it will look decayed and have pink/white fluffy patches.

Fish will often be lethargic, possibly not eat or hang in the water not moving much. The eyes will often have a white sheen over them.


Choose an anti-fin rot treatment. Aquarium tonic salt is also of great benefit when treating fin/tail/mouth rot, and can be used together with some medications, although always check the instructions before using together. As long as the damage to the fins or tail is not too bad, fish usually re-grow the damaged areas, although this could take some time.

Velvet Disease

The fish looks as though it has been dusted with icing sugar and will be covered by tiny white spots, which are much smaller than white spot.

The parasites are very irritating for the fish and it will have rapid gill movements and also vigorously scratch or rub itself against stones and ornaments in an effort to remove the spots.


Choose an anti-velvet disease treatment, and follow the instructions carefully. Aquarium tonic salt is also of great benefit when treating velvet disease, and can be used together with some medications, although always check the instructions before using together.

Swim bladder problems

The swim bladder is a gas filled sack inside the fish that helps it to neither float nor sink in the water.

When there are problems with it, the fish can either float and is unable to swim properly, or it may sink and be unable to swim up for long. There are many reasons why this can happen, including a bacterial infection in or around the swim bladder.


As there are so many causes of problems with the swim bladder, it is best to see a member of the store team for advice. Off the shelf treatments include swim bladder control treatments or an anti-internal bacteria treatment. Also aquarium tonic salt may help, as could improving the fish’s diet with frozen food as this will ease constipation if this is the cause.

You can always take a picture of your ill fish and bring it in to store. An experienced member of the store team can then help you to diagnose the problem and recommend appropriate treatment.

Here are some less common fish diseases you may encounter.

Red sore or sores on the sides of the fish


Ulcers as they get worse very quickly They are bacterial infection and often then get secondary.

Choose an anti-ulcer treatment or anti-bacterial treatment, and keep a close eye on the fish in case it develops a fungal infection in the wound. Aquarium tonic salt is also of great benefit when treating ulcers, and can be used together with some medications, although always check the instructions before using together.

Large external parasites

These can be seen on the fish and the two most common ones are fish lice and anchor worms. The lice look like either round discs attached to the fish, or little ‘bugs’ attached to the fish.

Anchor worm looks like a white or green thread hanging from the fish.


Do not try to remove the parasites as you may leave the mouth parts of the parasite still embedded in the fish’s skin. Choose an anti-external parasite treatment and follow the instructions closely. Once the parasites have left the fish Aquarium tonic salt can be used to help prevent infection while the wound heals, although check to make sure you can use salt with the treatment you have been using.


The fish’s scales are raised and make the fish look like a pine cone. Often the fish will be lethargic and not interested in food.


Choose an anti-bacterial treatment.

Slime disease

Excess mucus covering the body giving the fish a cloudy grey appearance. The fish will often have rapid gill movements and be lethargic


Choose a slime disease treatment.

Aquarium salt

This is a very useful addition to the aquarium first aid kit. It is a useful general tonic and many fish benefit from its addition as part of your care routine helping to maintain a healthy aquarium environment. also be used at a higher dosage level to treat and help treat some diseases. It is also very useful as a secondary treatment after you have treated for common diseases such as fin rot and white spot, to help the fish get back to full health.

Alternative and herbal treatments

There are several alternative treatments available now which do not use chemicals but instead use herbal compounds such as tea tree extract and Aloe Vera to treat some common fish diseases.

We stock a range of treatments in store available in an assortment of sizes to suit all tanks.

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