When is my aquarium ready for fish?

Wait until ammonia and nitrite levels have increased and then drop to zero before adding more fish. It usually takes 3 to 6 weeks for a new aquarium to go through the initial nitrogen cycle, so only a few fish should be added per week during this time. As your colony of good bacteria grows, you should be patient and wait before adding new fish to the tank. In the meantime, continue to test water and monitor ammonia and nitrate levels.

You'll notice a large increase in nitrite followed by a gradual increase in nitrates. This is usually a good indicator that the cycle is almost complete. During the fish tank cycling process, you should regularly test the water in the fish tank for ammonia, nitrite and nitrate. The easiest way to check the water in the fish tank is to buy a good complete measuring kit.

The key elements to consider are ammonia, nitrite, nitrate and pH. These compounds will largely be kept under control with a good mechanical, chemical and biological filter. But it's a delicate balance, so check the condition of the water in your tank regularly. Remember that you can always bring a 100 ml sample of water from your aquarium and have it tested free of charge at your local pet farm.

Now, a potential problem with this approach to bicycling a fish tank is that when you add the filter or filter medium from a cycled aquarium to your new fish tank, if the cycled aquarium is infected with harmful bacteria and viruses, you can also add those harmful bacteria or viruses to your tank. Your aquarium doesn't, as these elements break down and release ammonia into your aquarium water. But to be sure if your fish tank is undergoing a cycle or not, it's a good idea to test the levels of ammonia, nitrite and nitrate in aquarium water. If the pH of your aquarium water is lower than 7, it can slow down or stop the nitrogen cycle in your aquarium.

Many people recommend using some “tough fish” like the Guppies if you're setting up a freshwater aquarium or a damsel for a saltwater aquarium. If you find that the pH is lower than 7, making a water change of approximately 20% of the water in your aquarium can increase the pH of the aquarium water. So, if you add the filter or filter medium from a cycled aquarium to your new aquarium, you'll add the beneficial bacteria to your new tank. To start riding a bicycle, you must have your aquarium ready, this includes making sure that there is gravel in the tank, that the aquarium is full of water and that the filter is turned on.

Bicycling the aquarium is the process of establishing the biological filter, a colony of beneficial bacteria that live in the filter medium and process fish waste. However, New Tank syndrome can always be avoided by properly cycling the aquarium with a small number of fish and making the necessary additional water changes. The cycle of a tank or aquarium is commonly known as “the nitrogen cycle” and is the process in which several strains of nitrifying bacteria consume dangerous toxins in the water and convert them into safer compounds that fish and aquatic livestock can tolerate. You can see the peaks in the diagram above and once your & ammonia nitrites are at 0 ppm and your nitrates are below 5 ppm for saltwater aquariums and 20 ppm for freshwater aquariums, you can slowly start adding your first fish.

After testing the water in your aquarium for ammonia, nitrite and nitrate, if the reading shows 0 ammonia, 0 nitrites and some nitrates, then a fish tank cycle is performed.