Cycling a Freshwater Pufferfish Tank

When it comes to keeping freshwater pufferfish, there is nothing more important than an established tank – well, that and perhaps a steady supply of snails! Introducing a puffer to an uncycled tank is disaster waiting to happen. Fortunately, it doesn’t take very much effort to establish a fish tank – only patience.

All puffer fish lack the protection of scales, which makes them very vulnerable to toxins in their environment. For instance, elevated levels of Ammonia are toxic at a much lower concentration for freshwater pufferfish than they are to regular aquarium fish that have scales. When a fish tank enters the Nitrogen Cycle, it starts off with a very high level of Ammonia. Once the Ammonia is done spiking, the level of Nitrite in the tank begins to rise – a spike in Nitrate signifies the tail end of the cycle.

If you have other fish tanks in your house that are already established (i.e. at least older than 6 months), then you can transplant a small portion of their bacteria colony into your new puffer tank to jumpstart the cycle. Since the bacteria colonize on the hard surfaces, like filter media and gravel, it’s really easy to take a scoop of either one and place them in your new tank. It is important to note that you can only do this with healthy tanks – if you have recently treated your tank for fungus or parasites, then do not use this method to cycle your freshwater puffer tank.

Since there are many variables that factor into the time that it takes to cycle an aquarium, it can take upwards of two months to fully establish your new freshwater pufferfish tank. For instance, temperature, stocking, and the method used can influence the wait time – your tank is not ready for a puffer until the Ammonia and Nitrite read 0.00, and the Nitrate is at least below 20ppm. However, in most cases, it doesn’t take nearly as long – especially if you are transplanting a portion of an existing beneficial bacteria colony.

A freshwater pufferfish that is introduced into an uncycled aquarium will have a very low chance of survival, especially if you are not able to commit to large, daily water changes to help keep the toxic levels of Ammonia and Nitrite down. Puffer fish can make great aquarium pets if you do your research and take your time with set up, don’t ruin your chances of having a wonderful family pet because your tank hasn’t completed the Nitrogen Cycle yet.