Tails Blog

Water and an aquarium set up

Steve Coppell - Tuesday, May 22, 2012

It really does't matter how big your fish tank is or what you plan to keep, the condition of the water in your fish tank is often the difference between success and failure.

Why can't I add fish to my fresh clean water?

When you set up an aquarium for the first time, it's important that you age the water you intend to use in the tank before adding fish. Failure to do so will almost certainly end badly for your fish. 

What does it mean to age the water?

You will need to allow at least a week ( but it may take 10 to 14 days) between filling the tank and adding fish, during which time the filter system will develop a population of bacteria necessary for biological filtration. At some stage during this period a very high nitrite level will occur; when nitrates return to zero after this peak it will be safe to introduce fish.

So these bacteria are actually good for my fish?!

Yes, your tank water becomes polluted from fish waste, decomposing left over food and plant material. Ammonia is a by product of this process. The good bacteria convert the ammonia in tank water, to nitrites and then into less toxic nitrates. Nitrates are consumed by any plants in your tank and the water is made safe for your fish.

Can I speed up the process?

You can buy additives which speed the maturation process, but always monitor the nitrite levels with a test kit rather than relying on time estimates on the container. An alternative solution is to obtain a couple of handfuls of substrate from a mature disease free tank, which can be sprinkled on to your substrate to act as a bacterial starter culture. Likewise an active filter can be transferred to a new tank. 

Test the waters

It's a really good idea to regularly test the ammonia levels of your tank water. This doesn't have to be expensive or time consuming. Click on the device above to learn more about an easy to read stick on ammonia monitor.