How many fish can live together happily?
It is not how many fish can live together but how many fish your tank has the capacity to hold. This will depend on the size and type of fish. Your local pet shop or aquatic supplier will be able to advise you on what your tank is suitable for. Overcrowding a fish tank leads to competition for food and poor water quality due to the waste being produced. You will also need to consider which breeds of fish can live together.
It is very important not to overcrowd your aquarium. Too many fish in a small tank will cause water quality problems, and can also increase the spread of disease. A good guide is to allow at least 2 litres of water for every 1cm of fish. For example, if you have three goldfish of about 8 cm each, your tank should hold a minimum of 48 litres of water. It is also important to remember that fish do grow, so you should allow for the full adult size of your fish, not just the juvenile size.
Why are my fish flicking and rubbing themselves?
The most likely cause is skin irritation caused by skin or gill flukes - you should be able to get treatment for these either from a specialist aquarist shop or from your vet.
My pond is frozen with ice all over the surface – what should I do?
Your fish should be fine for a day or so, but if the freeze persists do not under any circumstances break the ice as this can cause shock waves to seriously affect the fish. Use heat to melt a patch in the ice and you can even siphon some water out to leave an air gap between the ice and the pond surface – air is a good insulator. However since the metabolism of fish is directly related to the temperature of the water they are in, they can cope well with the cold winter weather. They tend to just stay around the bottom of the pond until spring comes.
How do I calculate the volume of water in my aquarium / pond?
It is important to know the volume of water in your aquarium, for adding treatments and medicines to the water, and for working out many fish you can keep.
Multiply a x b x c in centimetres (cm). This gives the volume in cubic centimetres. Divide this number by 1000 to give you the volume in Litres.
Average Depth = 30 cm
Average Width = 30cm
Average Length = 100cm
(30 x 30 x 100) = 90 Litres
In feet and inches
Multiply a x b x c in feet. This gives you the volume in Cubic Feet (ft3).
Average Depth = 1.5 feet
Average Width = 1.5 feet
Average Length = 3 feet
1.5 x 1.5 x 3 = 6.75 ft3
There are six gallons in one cubic foot, therefore multiply this number by 6 to give you the volume in gallons.
6.75 x 6 = 40.5 gallon
How can I test the water in my aquarium?
There are a number of water test kits on the market that are available from most good pet shops. We recommend that you regularly test the pH, ammonia (NH4), nitrite (NO2), nitrate (NO3) and dissolved oxygen (DO) levels. It is important that the ammonia and nitrite are at a very low concentration, and that the pH is stable. The nitrate level is less critical because it is not dangerous to fish unless at very high levels.
How often should I change the aquarium water?
See above. Most aquariums should be cleaned every 2 weeks on average. It is easier to combine cleaning and water changes by using a gravel siphon, as this also removes any dirt and waste from the bottom of the tank.
Can I add tap water directly to my aquarium?
Tap water contains chlorine and chloramines, which are added to our water supply to act as a disinfectant. They are very effective at keeping the water clean for human consumption, but unfortunately fish cannot tolerate chlorine or chloramines. You therefore need to add a dechlorinator to the water before adding it to your aquarium. In all other aspects, tap water should be perfectly safe for fish. However, it is also good to know the hardness of your tap water.
What is a biological filter & what does it do?
The biochemical function of the aquarium filter is to remove harmful substances from the water by biochemical reaction. This means that bacteria within the filter can alter a substance (for example, ammonia) to turn it into something else.
Nitrifying bacteria are responsible for removing dangerous substances called ammonia and nitrite from the water. They do this by using a small amount of oxygen to change the chemical composition of the toxic substances, and in doing so, turn them into nitrate. Nitrate is relatively harmless to fish, and can be easily removed through water changes and by live plants, which use it as a food source.
Once a filter has been established in a tank for several weeks, it becomes ‘mature’, meaning that there are enough bacteria in the filter to cope with the amount of waste produced by fish. If a tank is overcrowded, then problems will continue to occur, because the filter will not be able to cope with the large amount of waste.
In new tanks, the filter is not mature, meaning that it has not built up any bacteria. New tanks should be ‘cycled’, without any fish in for at least two weeks before adding fish. When adding fish, it is best to add a few at a time to allow the filter to mature gradually, otherwise the amount of waste will overwhelm the filter and as a result fish may die from ammonia or nitrite poisoning.
What causes cloudy water?
Cloudiness is usually caused by a bacterial bloom – which are usually harmless. Cloudiness is common in new aquariums. If your water is cloudy, then you should increase the aeration and make sure that the filter is working correctly. Siphon the gravel and change a small amount of the water (20%) regularly until it goes away. Also be sure to test the water to make sure there is not an underlying problem. Sometimes cloudiness can be caused by over feeding, or by failing to remove any uneaten food. If this is the case, then you may have a wat