Many new fish keepers usually go to a fish shop and buy a tank, the needed supplies, and fish. Taking the advice of some fish store employs they go home, set up their tank, and add their new fish or purchase fish right after set up .
A week or so later, they are back at the shop buying more fish to replace the ones that just died for no reason.
Many new to the hobby have no idea why or how to cycle a fish tank.
Beneficial bacteria are needed for fish to survive.Just the same as us humans require beneficial bacteria to survive.
Firstly, the Nitrogen Cycle
A new fish tank needs to go through the Nitrogen Cycle to be considered cycled (AMMONIA to NITRITES to NITRATES).
Ammonia and Nitrites are harmful to fish. Nitrates in high levels can be harmful to fish. But are easy to control by keeping your tank clean and doing regular partial water changes.
Ammonia will cause breathing problems for fish, as the amonia burns their gills. Ammonia/Nitrites in any amount is not good for fish.
CYCLING WITH FISH
To establish beneficial bacteria in a tank,we must first supply something for them to “feed” on.
To do this, put one or two hardy/cheap fish in your new tank and wait 3 to 5 weeks before adding a few more fish. Danios, neons or guppies are useually a good choice. Feed sparingly at first.
Ideally you should have a test kit or talk to your LFS as they usually will test a sample of water for you for a small fee.
After two-three days of having a new tank set up, ammonia should start to appear and then spike. Each tank is different. Nitrites will then begin to show. Like the ammonia, nitrites will start at small numbers and then quickly get higher. When the nitrites decrease back to zero and an acceptable level of nitrates are shown, your tank is cycled.
Do not add to many fish at once. It is safer to add fish in small numbers to make sure the bacteria numbers grow to can handle the number of fish in the tank.
FISHLESS CYCLING
The benefit to FISHLESS CYCLING is that it grows bacteria in the tank before any fish are injured or killed. When ammonia and nitrite levels fall to zero, beneficial bacteria will be established to break down the waste. There are many different opinions about/ ways to do a FISHLESS CYCLING.
Using household ammonia (no perfumes/coloring/etc.)
Add 2-3 drops of ammonia per 50 litres of water everyday until ammonia reaches 5ppm (no water changes). After reaching 5ppm (maintained) add the same amount of ammonia daily until nitrites are detected. As the nitrites increase, and the ammonia decreases at a faster pace, decrease the amount of added ammonia in half. As the nitrites increase, the ammonia levels should decrease rather fast (even after adding ammonia daily). It takes about one month to complete a FISHLESS CYCLE. Just like cycling a tank with fish, when the ammonia and nitrite levels show zero, and nitrates are detected, the tank is cycled.
Established tanks with AMMONIA, NITRITES and high NITRATES
An established tank can have an ammonia or nitrite spike, usually because something has killed off your beneficial bacteria. These are some of the possibilities that may have caused it:
1. Lack of oxygen (pump/air flow to small for tank, power outage, etc).
2. Over cleaning the tank gravel and/or the filter media
3. Cleaning filter media in clean/fresh water. It is best to clean filter media in used tank water.
4. Over stocking and over feeding your fish.
5. Water needs to be dechlorinated when you do a water change. Chlorine/chloramines will kill beneficial bacteria
