Filtration is also very important in a cichlid tank. Most species of rift lake cichlids grow to be 4"-8" long. Due to their territorial nature, you will need to keep the tank stocked to reduce aggression. So adequate filtration is an absolute must.
Fishtank filters take advantage of a natural biological phenomena called the "nitrogen cycle" which converts toxic ammonia into non-toxic nitrate. Ammonia is produced by fish waste and uneaten fish food. Nitrosommonas spp. bacteria oxidize the ammonia into another toxic chemical: nitrite, and Nitrobacter spp. bacteria oxidize the nitrite into nitrate. Nitrate is then consumed by plants, removed by water changes and converted back to nitrite by anerobic bacteria and cyanobacteria (blue-green algea). Maintaining 0 ppm levels of ammonia and nitrite depends on keeping colonies of Nitrosommonas spp. and Nitrobacter spp. Since these bacteria are aerobic, they require an oxygen-rich environment. This is why canister filters constantly move water through the media and why trickle filters (which are basically "damp" filters) are so effective. If filters are shut down for more than an hour or so, the aerobic bacteria rapidly begin to die as they consume their supply of oxygen.
When you set up a new tank, it will have very few of these bacteria in it. Add a few fish to create a source of ammonia and wait for the tank to "cycle." During this time, the ammonia level will spike and the fall off as the population of Nitrosommonas spikes and stabilizes. This will be followed by a jump in nitrite as the population of Nitrobacter spikes and stabilizes. A "cycled" tank is one in which the bacteria populations have reached an equilibrium such that ammonia and nitrite are 0 ppm. This process takes about a month, but you can make it go faster if you use a small about of gravel or media from an existing tank in your new filters. Never water change the tank during cycling, even if the fish look stressed, or you will just prolong the process.
For small tanks such as a 20 or 40 gallon, I suggest a HOT Magnum Pro or Fluval 203 canister filter. For larger tanks I suggest a couple Fluval 303 or 403 filters. On my 90 gallon I had a Fluval 303 and a Magnum 350 Pro. The 155 gallon I currently maintain has two Fluval 403s and a Magnum 350 Pro.
I always recommend canister filters over power filters because they are easier to clean, more efficient, and reduce evaporation. As far as brands go, I recommend the HOT Magnum Pro as an excellent small canister filter. It mounts on the back of the tank like a power filter, with all of the advantages of a canister filter. For larger tanks, I recommend the Fluvals, which are inexpensive and tough. My Fluval 303 is 15 years old and still running! The larger Magnums seem more fragile than the Fluvals, although they are easier to start. I definitely recommend adding a BioWheel Pro 60 as a trickle-filter. Just make sure they don't dry out because the filter has clogged or your filter bacteria will die.
Filters should be cleaned once a month. If you have two filters, you can alternate between them so that each one gets cleaned once every two months. When cleaning, replace the carbon and rinse the media in water which is the same temperature as the tank. You shouldn't have to clean the BioWheels at all; if they clog with algae just pull the algae off with tweezers.
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Last modified at Saturday, April 28, 2012