After completing the previous stage, many beginning aquarists head out to the aquarium store to buy their Betta. It’s safe to say this is not the best idea: an aquarium is not safe for fish immediately after set-up. Unfortunately a few weeks of waiting is required, during which time you work on getting the nitrogen cycle up and running.
We’ve already briefly touched on this topic in the chapter about Betta bowls. I’ll repeat it one more time for the people in the back: without a nitrogen cycle an aquarium quickly turns toxic and you should never place fish in an uncycled tank. The reason for this is that it’s lacking important beneficial bacteria colonies that should inhabit the filter media and substrate. These colonies convert extremely toxic ammonia/ammonium (NH3/NH4), which is excreted by fish and anything that might be decaying in the tank (like leftover food bits and dead plant leaves), to equally toxic nitrite (NO2) and finally the more ‘acceptable’ nitrate (NO3). This last substance is not nearly as damaging to your fish as the others and will be used by live plants to grow, or removed by you during a water change to avoid excessive levels.
Alright, so you need to get those beneficial bacteria growing so ammonia/ammonium and/or nitrite don’t end up sending your Betta to fishy heaven within a few days of purchase. But how do you go about this? I’ll explain it in short here. If you’re still unsure after reading the short version or just want to know more, just head over to the Aquariadise article on cycling an aquarium, which should contain everything you need to know about cultivating those important bacteria.
Fishless vs. fish-in cycle?
There are two ways to cycle an aquarium. The fish-in cycle is the ‘classic’ one and involves placing fish in the tank which excrete the ammonia needed to kickstart things. Not at all my favorite method, as these fish are exposed to high levels of ammonia and nitrite and might not survive. Instead, we’re going for a fishless cycle here. Easier, faster and better for your fish.
What do you need?
In order to get your Betta tank cycling, all you need is the water test kit you bought during the preparatory stage and a bottle of pure ammonia. Household ammonia without any added scents or surfactants is a cheap option, but if you can’t find it then luckily there are also aquarium brands out there that sell it. Some aquarists like to use pieces of fish food and let them decay in the tank in order to produce the ammonia they need, but let’s be honest here: it’s a little gross.
To start your cycle, add about a drop of ammonia per gallon of aquarium water. Your ammonia test should now show visible levels of this compound; keep testing a few times a week. Once the ammonia levels have dropped back to zero, dose again and continue testing. If all goes well, nitrites should start popping up soon as well: a sign things are heading in the right direction. Keep dosing whenever needed until both your ammonia and nitrites drop down to zero and you’re getting a visible nitrate reading. Congrats, you’ve got a cycled tank! Remember to keep adding a little bit of ammonia now and then to keep your beneficial bacteria alive until you’re ready to introduce your Betta. Do a large water change before the introduction to get the nitrates down to an acceptable level (ideally < 10).