Cycling a fish tank has nothing to do with a two wheeled vehicle; it also does not mean to simply let the tank run with water for a week or two. Cycling refers to getting the Nitrogen Cycle established in a tank. The Nitrogen Cycle is what makes it possible for us to keep fish in glass boxes which are, essentially, their own toilets. The Nitrogen Cycle starts with ammonia, which is the result of fish metabolism, dead plants, etc. and which is very harmful to fish; a certain set of bacteria convert the ammonia into nitrite. Nitrite is also pretty harmful to fish, and a second group of bacteria convert nitrite into nitrates. Nitrates are much less harmful to fish, and nitrates can be removed by having lots of live plants, or doing frequent regular water changes. There are also just coming into the hobby a number of products, both as additives and entire filtration systems, that will house the group of bacteria (which need a low oxygen environment = anoxic or anaerobic) that convert nitrates into harmless nitrogen gas. This last stage of the Nitrogen Cycle works very much the same way that live rock works in a Berlin style marine tank. The technology is coming to the tropical fish hobby/industry from the commercial aquaculture of food fish industry -- and it is now possible to complete the cycle without doing weekly or regular water changes.

The requirements for the Nitrogen Cycle to get going in a fish tank are 1) the bacteria -- they can be allowed to build from the population in any tank, or they can be "seeded" by adding gravel, plants or filter stuff from an established tank into the new tank, or from any of the liquids or powders available as tank starters at your lfs. 2) The bacteria need a place to live  -- which is usually part of the filtration system of the tank, although the bacteria actually live on every surface of the aquarium. 3) They need food -- in terms of ammonia to start with, then the nitrite that is the product of converting the ammonia -- the food can be in the form of adding ammonia directly, or from the fish.

It is very important to understand that without all three components -- the bacteria themselves, places for them to live, and food for them -- the Nitrogen Cycle will never become correctly established in a tank. There are many ways to get the Cycle started in a new tank. One is fishless cycling which involves adding ammonia (or letting some cocktail shrimp decompose) to the tank in enough concentration and over time for the bacteria of the NC to get going. The problem with fishless cycling is that most folks do not want to look at an empty tank for 4 -- 6 weeks while they feed ammonia to the bugs, or watch a few shrimp decompose. You can also get the NC going by adding something to "seed" it from a healthy existing tank. This can be a sponge filter, plants, gravel or filter medium. In my experience what works best, especially for new hobbyists with their first tank, is to use Nitrogen Cycle starter products from the lfs. These can be in the form of liquids with millions of live bacteria, or dry powders with suspended bacteria and food to get them started.

I have tested all of the methods for starting the Nitrogen Cycle in a new tank, and in my experience what works best is to start the new tank with bacteria either in liquid or dry form (and to add any "seeds" you can get), and to slowly add fish to the tank over a 4 -- 6 week period. You should absolutely buy your own testers for testing "The Big Four" -- pH, ammonia, nitrite and nitrates. The test strips work just fine, and they are the best investment (other than a good book) that newbies can make in their aquarium hobby. LFS's like to encourage folks to bring in water for them to test, which is fine -- except that the Nitrogen Cycle and how it works is so critical to understand that it is really important that you do the testing yourself -- don't just rely on your lfs telling you that things are "ok". You need to have the numbers for "The Big Four", and to keep track of them in a log, as the direction/trend of any tank parameter is much more important than the absolute number -- unless the numbers are so high as to really threaten the health of the fish.

Bottom line, for me -- buy some test strips to test ammonia, nitrite, nitrates and pH -- add some "starters" either from the lfs or from existing healthy tanks -- add the fish over a 4 -- 6 week period -- test "The Big Four" each time before you add new fish, and keep a log -- don't rush things, and most important  --- LEARN ABOUT FISHKEEPING AND HAVE FUN!

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Local Fish Stores -- "The Heart of the Hobby"  

If life gives you lemons, squeeze them into people's eyes and run away!

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I over cleaned my gravel.  I didn't have any bacteria start to grow until I actually stopped weekly water changes and gravel vacuuming and let the tank sit for almost a month. 

--Fisher

If your not learning something new everyday, your not paying attention!

My question is.... How do I know when I have to many fish in my tank?  Like I said, I have a 55gal tank and at this time I have the following fish;

1 6yr old Blue Gourami; 1 6yr old Tiger Barb; 1 2yr old Kribensis (female); 1 6mo old Red Fin Shark; 1 6mo old Red Tiger Platy; 1 6mo old Pacosamus; 1 6mo old Giant Gourami; 2 6mo old Jewel Tetra; 2 6mo old Glass Tetra (red eyed); 2 8mo old Multicolored Cichlids; 4 6mo old Sailfin Mollies (2 blk, 2 wht); 2 6mo old Pineapple Swordtail Platies.

All together I have 19 fish in my tank and am wondering if I should remove some of them as I am learning more about the size each of them are going to grow in size.

Thank you for your input.

jpk

jpk