The Simplest Cycling Explanation EVER:
One of the most daunting things about fishkeeping to the beginning hobbyist is the prospect of "cycling" a tank. What does this mean? It's actually very simple. When fish are in an enclosed fish tank as opposed to a lake or stream, their poop (waste) has nowhere to go. The waste builds up in the tank, creating ammonia (ammonia is invisible). So basically your fish are swimming in their own poop/feces. This will kill your fish. The ammonia burns their gills. It's not nice. So what to do? Well, bacteria will start to grow in your tank that will eat the poop. This bacteria is called "nitrite." Unfortunately, the nitrite levels in your tank will also rise and will also kill your fish. So, to eat all this nitrite, "nitrate" starts to grow. Nitrate is much less harmful to fish. However, this too will start to build up over time, and this is where the water changes (see below) come in with your trusty water siphon. Every week you should change out 25% of the water in your tank and replace it with new treated tap water. This keeps the nitrate levels down. This is essentially what happens when you cycle a tank. So how do we get it to do all this? There are four main options: Fish Cycle, Fishless Cycle, Established Media Method, and Bio Spira. You will need a Freshwater Master Test Kit that tests for Ammonia, Nitrite and Nitrate. I recommend the "Freshwater Master Test Kit", available from Amazon for the best price around. Click here to order the test kit I use.
Fish Cycle:
If you've reached this page because you have fish mysteriously dying in your tank already and you have no idea what to do, never fear, here is the information you need to get through the cycling process. Adding fish to a tank immediately is the fastest way a beginner kills their fish without even knowing what they did wrong. Ammonia build up is a silent and invisible killer, even if the water is crystal clear, there is likely still ammonia present. So what do you do now? The absolute best option would be to return some or all of the fish. I've yet to see any new fish owner willing to do this...so how do you keep them alive? Assuming you've read the above, your fish will soon be swimming in a giant pool of their own poo. You've got to get some bacteria from an established fish tank that will start your tank cycling. Try the Established Media Method (see below) if at all possible. If you know no one that has an established tank that will lend you some gravel or filter media (try a fish store too!), besides Bio Spira (see below), your only option is to cycle the tank with fish in it. This means you have some work ahead of you. YOU are all your fish have to depend on for their survival, so please don't slack here. Since ammonia and nitrite will kill your fish, you must keep these levels as low as possible. Preferably, below 1.0 ppm. This means that depending on the size of your tank and your level of stocking, you will have to do water changes almost daily just to keep the levels safe for the fish (See below section on "Water Changes"). With your new trusty test kit, you'll need to be testing your water daily for your ammonia, nitrite, and nitrate levels. As soon as either your AMMONIA or NITRITE go above 1.0 ppm, you need to do a water change (see below for how to do a proper water change). Levels above 1.0 ppm are toxic and deadly to fish. It may take several water changes to get them to safe levels and this can be a real pain in the you know what, but is absolutely necessary. Ammonia will burn your fishes' gills, it's cruel to allow them to suffer. This process will take several weeks to complete, see the above explanation of what to look for. Once both the ammonia and nitrite levels are regularly 0.0 pmm and you have a trace of nitrate in the tank, you're done! Whew!
Now, why shouldn't you just go out and buy a bunch of feeder fish to cycle the tank for you? Not only does cycling a tank with fish in it take much longer than the other methods, but these "feeders" are generally not very healthy since they are kept in bad conditions. When you put these fish in your tank, you are adding diseases to the tank that will not disappear when those fish are removed. Ick can stay in your tank, along with lots of other nasties that will kill off your expensive fish. Why risk it?
Fishless Cycle:
Since ammonia will hurt and kill your fish, the most humane thing to do is to fishlessly cycle your tank. To do this, you will be adding the ammonia directly to your tank without waiting for your fish to fill the tank up with waste. The most difficult part of this is finding the pure ammonia. You will need to find a bottle of pure ammonia. It can NOT have soap suds, fragrance, or coloring. Look at the label, it should say 100% pure ammonia. Call the company number if you aren't sure, there is usually a service number printed on the bottle. The ammonia should not cost more than $3.00, I purchased my one and only bottle at a Hardware store. Once you have the ammonia, you will add it to your newly set up fish tank. The tank should have water in it, all the ornaments and gravel, heater, and filter set up and running. Raise the tank temperature to 85 degrees. The warmer temperature will help the tank cycle faster. Add a couple of drops of ammonia to the tank, do not add too much! Wait 20 minutes, then bring out your trusty ammonia drop test kit. Take a sample of your water and test for ammonia. The ammonia level should be around 5 ppm, if not, add more ammonia. This level is toxic to fish, but since there are no fish in your tank, this is fine. Now that you have the ammonia in your tank, you can sit back and relax for a week. After the first week (give or take), test your water for ammonia and nitrites. Your nitrite level should be starting to climb and your ammonia level should be starting to decline. If this is happening, add another drop or two of ammonia to feed the nitrite bacteria, keep the ammonia levels up as needed. Over a period of time (anywhere from a couple weeks to a month depending on the tank) Nitrate will start to build up in your tank and the ammonia/nitrite levels will reach 0. Once you have a reading of 0 ammonia, 0 nitrite, and 5+ Nitrate, you are ready for fish. Do one large water change, around 50-75% (the goal is to get the Nitrate to a safe level), lower your water temperature to 78 and add a few (see "What Kind of Fish?") of your first fish. Closely monitor the tank for any ammonia or nitrite spikes. If the tank remains stable for 2 weeks, you can start adding more fish slowly, 1 or 2 at a time.
Established Media Method:
My personal favorite and the method I use personally to start all of my tanks. Once you have one established tank, there is no need to ever cycle a tank again. Yay! How do you do it? Since an established tank already has all of the necessary bacteria in it, you need to get some of it into your new tank. The easiest way is to grab a handful of gravel from the established tank and throw that in the new tank (with treated water of course, untreated water can kill your bacteria!). If you don't like the color of the gravel, you can easily put the cycled gravel in a pantyhose and put that in the tank.You can also steal some filter media from the tanks filter and add that to your new filter (filter media can be cut down to size). Of course, using this method, monitor water parameters with your test kit and only add fish one or two at a time.
Bio Spira:
I've never personally used this since I always use the Established Media method, but here is what I know about it. Supposedly, this little sac holds all of the bacteria necessary to completely cycle your tank within minutes. You add it to your tank, add the fish, and you're done. Sounds simple to me...but there are some pitfalls. It must be refrigerated at the fish store. If they have it sitting out on the counter, don't waste your money, it won't work. It's expensive, especially if you have to buy more than one sac for a larger tank. If you have already had fish in your tank and the ammonia levels have risen, when you add it to the tank, the bacteria will just die. Your ammonia levels must be at 0 for it to work, so do not add to a tank that already has high ammonia levels. The products "Cycle", "Ammonia Down", and several others are just junk and I do not recommend them. Some fish store employees will try to sell you on these, but they are basically worthless products that will not do what they promise. Use common sense, do you really think something alive is living at room temperature in that little bottle on a store shelf for years at a time? Didn't think so, these won't help to cycle your tank for you and are a waste of money.
Water Changes:
Why do I need to do water changes? When the water evaporates, can't I just add more water to the tank and call that a water change? No. Over time, nitrate levels in your tank start to build up. A small nitrate reading below 20 is ok to maintain in a tank, however if it gets higher, that means it's time to do a water change. The best way to do a water change is with a water siphon (see "How to Use a Water Siphon" below). Change out 25-30% of the water, dump that out, and fill your bucket back up with tap water close to the temperature of your fish tank. If the temperature isn't close to that of your tank, your fish may go into shock. Treat the water with water conditioner BEFORE adding it to the tank, then dump it in. Voila! Water change! You can not just add water when it evaporates because when water evaporates, all that leaves the tank is the water. The nitrate and minerals still build up. If you don't remove some of those, the levels in the tank will continue getting higher and higher. Regular water changes are a good habit to get into. They keep your fish happy and healthy. I also find that regular water changes help young fish grow faster and also helps older fish develop brighter colors. Who wants a tank full of dull colored lifeless fish? Do your water changes!
How to Use a Water Siphon:
When I first jumped into the hobby...I couldn't figure this thing out for the life of me. Lots of splashing, sucking, and buckets of water later, I figured it out. Let me share my method with you so you don't have to suffer a fish water bath! First things first, make sure your siphon is connected and doesn't leak. Most come assembled. Make sure all the water is out of the tubing. Take a large, clean bucket (I use 5 gallon painter buckets), and place that below the level of the tank. Stick the larger end of the siphon into the fish tank. The tube end should be sticking out. Put the tube up to your mouth, and carefully watching the hose part, do a big suck like a giant straw. The tank water should go up and over the side of the tank, quickly point the tube downwards towards the bucket, and your flow of water should be established. If not, clear the tube and try again. FYI, I am a total germ-a-phobe, and I have never gotten fish water in my mouth. Simply rinse the tube end that your mouth goes on before each gravel vacuuming session. Take the gravel vacuum, and put it down over pieces of gravel and lift. You should see the fish poop and debris getting sucked up the siphon and out into your bucket. To stop the flow of water, lift the vacuum out of the water.
Disclaimer: This explanation has been simplified for easy understanding. For a more scientific explanation about nitrification, nitrifying bacteria, etc. please do further research. This basic information is sufficient to safely start and maintain a fish tank successfully.
