Cycling an aquarium basically just means allowing the tank time to establish the microorganisms and bacteria that are essential to fish health. If a tank is not cycled properly before introducing fish, the fish will die, poisoned by toxins created from their own waste. It can take months to establish a tank properly and it can be done in several different ways. I have always had a preference for the use of aquatic plants and conditioned filters. A conditioned filter is one that has recently been used in a mature aquarium and already contains many of the beneficial bacteria needed to break down the ammonia produced by fish waste or decaying plants cycling it into nitrites and nitrates. The nitrates and ammonia can build up in a tank and be extremely toxic to the fish so regular partial water changes help to reduce the levels. The plants require the nitrates as fertiliser to grow but will also create unwanted ammonia when they decay in a tank. Tap water has high levels of chlorine in it to make it safe for drinking, unfortunately the chlorine will kill many of the beneficial bacteria in an aquarium so it is important to allow it to stand for at least 48 hours before doing a partial water change It is usually recommended that you change between 20 and 30 percent of the water on a weekly basis to remove ammonia, nitrites and nitrates.
It usually takes about a week or more for the bacteria to efficiently reduce the toxicity enough for the fish to survive which is why many fish will die within that first week when introduced to a new set up. If you already have a mature aquarium and are setting up a new one you can use water or gravel from the mature tank to speed the process along. Using a filter from an existing set up is far more effective though. Filters should be cleaned in aquarium water and not with tap water in order to keep the beneficial bacteria levels up. Once an aquarium is cycled and planted, it pretty much looks after itself and very little maintenance is actually required. The filter media should be removed and cleaned in the tank water on a weekly to monthly basis depending on the set up. Water changes should be performed weekly and sometimes more frequently depending on the circumstances taking care to remove water closest to the gravel where most of the fish waste sinks and topped up only with water that has been standing long enough for the chlorine to have dispersed.
The more plants you have the better oxygenated your water will be and also the lower the nitrate levels will be as they feed off nitrates. I recommend having lots of plants of different varieties. They help provide your fish with the perfect habitat, using up waste products, improving water quality and providing cover for fry. They really are an important aspect in making the most of your fish and only become a problem if they become overgrown and limit swimming space for your fish. The only other negative thing I have to say about them is that you can sometimes get more than you bargained for and end up with a snail infestation that can be difficult to get rid of. However the snails in themselves can also be beneficial if you do not have algae eating fish as they will help keep your aquarium free of it and will scavenge any food that litters the bottom of the tank that would otherwise pollute the water. They do become a real nuisance though if you are trying to breed egg layers as they will also eat the eggs.
When I am setting up an aquarium I use small stones or rocks to weight my plants down and help them take root in the gravel or substrate. I use all kinds of different types, colours, shapes and sizes to mimic a natural environment and make it as interesting as possible. I create hiding spots and caves with the rocks for the fish to hide in. I also use bogwood nowadays although not initially. The only artificial decoration I have is a plastic volcano a fairly recent addition which just serves as a hide for both my fish and air stone. I have recently added air stones and LED night lighting to my tanks. I did not have them before and was still very successful in breeding the Livebearers just using natural decorations that were easy and inexpensive to source. I did however boil anything I added for at least twenty minutes beforehand in order to sterilise it. I replenish my plants a couple of times a year. I monitor the water temperature regularly as heaters can break down or become less efficient over time.
The real secret to success though is constant observation, your fish will tell you very quickly if something is far from ideal just from their behaviour alone. Sometimes it is necessary to quarantine sick or stressed fish which is when having more than one tank really helps. If a heater or filter breaks down and you don’t live near a pet shop having an extra tank can make all the difference. Alternatively it is good practise to keep a spare of anything that is crucial like heaters or filters if you don’t have another tank. Spare lights aren’t essential, your fish won’t suffer too much without them but your plants won’t grow or be as healthy without them.
I have not been immune to fatalities over the last five years and sometimes they are unavoidable but generally speaking I have successfully kept and bred far more fish than I have had losses and hope that this shall continue to be the case. I have given well over a hundred fish away in this time and was given around twenty five in total in the early years. I then went on to buy another seventeen years later and twenty more recently of which the mortality rate was terribly high but more likely to do with how they farmed or kept prior to being sold rather than my negligence.