When you buy your new aquarium it can be tempting to stock it with lots of fish right away, but all tanks need time to establish helpful bacteria before being stocked or you risk mass die-off of your fish. New tank syndrome occurs when too many fish are introduced to a new aquarium before ideal conditions have been established. The fish produce waste, but there are insufficient bacteria in the tank to consume and neutralise this waste. As a result, the ammonia levels in the tank rise and the fish suffer ammonia toxicity, which is usually fatal.

Signs of high levels of ammonia in your tank include water that smells stale and appears cloudy. Fish exposed to high levels of ammonia will experience breathlessness and damage to their gills. They will gasp for air at the top of the tank and desperately look for a way to escape their unacceptable living conditions. Here's how you can avoid new tank syndrome:

Cycle Your Aquarium

Allowing you aquarium to go through the natural cycle of establishing healthy bacteria to keep ammonia levels in check will ensure you have a healthy tank environment for your fish. Bacteria need food, in the form of fish waste, and a place to call home in the tank. A filter makes an ideal home for bacteria as their food source is brought straight to them, so opt for the biggest filter suitable for your tank.

To begin the natural cycling process, place just a few hearty fish in your tank that are naturally resistant to ammonia toxicity. Your local aquarium shop can advise you on suitable types of fish depending on what you eventually want to stock your tank with as some varieties need to be kept apart. It's important to start with just a few fish as too many will cause a surge in ammonia levels before bacteria have been established. You should also be careful not to over feed the fish as excess food creates waste that contributes to ammonia levels.

For the next few weeks, remove some of the water from the tank every few days and replace it with clean water that's been treated to remove chlorine and chloramine, both of which can kill the bacteria you're trying to establish in your tank. Your aquarium supply shop can tell you much water to replace based on the size of your tank and filter. Changing the water will prevent the ammonia concentration from reaching toxic levels, and you should also use an ammonia test kit to check the levels of ammonia in the water each week.

When enough bacteria have established themselves in your tank, the ammonia tests will show there are only trace levels of ammonia in the tank. At this stage, you can begin to populate your tank with whatever fish you'd like, but you should add just a few new fish at a time as suddenly loading the tank up with fish can create an imbalance once again between the bacteria levels and ammonia in the tank.

If you notice signs of ammonia after your tank has gone through the cycle of becoming established with a healthy colony of bacteria, you either have an overpopulated tank, the water isn't being filtered effectively, or you're over feeding your fish. Your local aquarium supply shop can advise you on the best type of filter for your tank and the optimum number of fish based on the size of the tank and the types of fish you already have.

Contact a company such as Salt Aquariums if you want to know more or have other questions.