The point of this discussion is to talk about mistakes people make in setting up and maintaining their aquariums but the real issue is water quality. All of these mistakes affect water quality and as a result the health of the fish.
The key to good water quality as I have said before is water changes. Let’s face it, if you had a system where the water was changing constantly and being replaced completely every half hour there would be little chance of a buildup of pollutants. I don’t know of anyone who has such a home system and who could afford the water (and heating) if they did?
So without this constantly changing water, pollutants are bound to build up so how do we control them? The first way is… you guessed it, water changes! So the first mistake is not making large enough or frequent enough water changes. A simple guideline is 10% to 20% every week.
The second mistake (although it could be the first mistake that people make) is adding too many fish to the tank too fast. If you have any experience with aquariums, you know about the biological filtration and the nitrogen cycle. For those of you who are new or need a quick refresher here is my simplified version.
Fish produce waste in the form of ammonia. Left over food decays and produces ammonia. Ammonia is toxic to fish. There are some bacteria that consume ammonia and turn it into nitrite. Nitrite is only slightly less toxic than ammonia. There are other bacteria that convert nitrite into nitrate which is nearly harmless (although large concentrations can cause problems). That is the basic nitrogen cycle.
Anytime fish are added to a tank, it takes a couple of weeks for the levels of the ammonia eating bacteria to adjust. The ammonia eating/nitrite producing bacteria have to do their thing before the nitrite eating bacteria can begin to build up. The nitrite eating bacteria are slower to reproduce than the ammonia eating ones so it takes another four to six weeks for them to stabilize things.
If too many fish are added too fast the ammonia and or the nitrite levels can build up to toxic levels before the bacteria can adjust and the result is a trip to the store to replace your fish so slow and easy wins the race and saves your fish and your money.
That’s all for now. Next time, two more mistakes. As always, please leave your comments below.
PS. I purposely did not give the names of the bacteria because I find that people get confused about which is which and I really don’t think it is important. My apologies to any biologists out there.