How to cycle a tank so that it's ready for fish.

Seen as I mentioned the nitrogen cycle in one of my posts a few days ago, and seen as I am currently going through cycling a tank, I thought I might as well share with you what the tank goes through. It's not exactly the most visually stimulating thing ever, but it is interesting to see the chemistry behind the cycle.

I currently have (courtesy of my boyfriend's brother - THANK YOU, MARK!) a 19gallon fish tank sitting on a kitchen bench. It is about half full at the moment and there are two filters running. One of my old filters and the old filter Mark used to use in the tank. It has black substrate in the bottom.

To start the cycle off you need a source of ammonia. An older, and less humane way some people cycle a tank is with some 'hardy' types of fish. These fish produce waste which help kick start the tank into a cycle. This could be done with some cheap goldfish or platies. Regardless of whether these fish are more likely to survive in ammonia riddled water whilst your tank cycles, does not alter the fact that these fish will be living so in a lot of discomfort. Damage such as ammonia poisoning and burns to their scales will be extremely common and may be a reason why fish die when people keep fish and don't do research. This poor goldfish is extremely unhealthy with ammonia burns to his scales and fins.

The best way to cycle a tank without animal cruelty is by simply providing a source of ammonia a different way. You may get pure ammonia from chemists or pharmacies or you can do what I do, and produce the source of ammonia through rotting food by adding one or two fish flakes every couple of days. It's that simple and it is not necessary to put any living creatures through harm. If you are going to do it using pure ammonia, please look up how much to use and when, as I've never done this myself before.

My tank!


I have been dropping a few flakes in every couple of days and this is where my cycle is at as of today!

In the picture you can see that the green tube is my ammonia reading, the purpley blue is my nitrITE and the yellow is my nitrATE. My ammonia has turned from a pale yellow with is a reading of 0ppm* to a reading of 0.5 ppm. This shows that there is some ammonia present and that a cycle will start. My nirtrITE has turned from a pale blue to a pale bluey purpley colour which shows that some of that ammonia is being changed into nitrITES with a reading of  0.25ppm. My cycle has officially started! And as for my nitrATES reading, this shows that it has not changed at all is still reading 0ppm. This means that the cycle is far from being complete. In case you're thinking that my numbers are ridiculously small, even a reading of 0.5 ammonia can be too toxic for a lot of fish.


*'points per million'.