At one time or another, most of us have set up a new tank, or have done a total reset/clean out of an existing tank. We at JDTropheus do that all the time. In the vast majority of cases, we do it without any problems. We would like to share with you some of our philosophies and thoughts about doing this.
Considering that the water conditions in Lake Tanganyika are generally very good, Tropheus keepers find it necessary to make frequent, usually once a week, water changes to try to simulate their natural environment. Nothing else takes the place of weekly water changes to help keep the artificial environment of a fish tank as clean and pristine as possible. It helps to remove anything that is accumulating in the water that the filtration system cannot completely remove, and is therefore a very important part of regular maintenance on any fish tank, but particularly for Tropheus keepers.
Tropheus do not face problems with high ammonia/nitrite/nitrate levels in their natural environment. Even seemingly small concentrations of chemicals can cause Tropheus to become ill or even die. One of the most dangerous problems that Tropheus keepers face is high levels of ammonia and nitrites, particularly when setting up a new tank or resetting an old one. A high level of these compounds can kill Tropheus quickly and with little visible sign of trouble. About the only visible signs, if you are lucky enough to catch them, is heavy breathing and occasionally the fish will swim very erratically right before it dies. Should you see this happening, immediate testing and appropriate action are called for.
The conversion from ammonia through nitrates by beneficial bacteria is commonly referred to as cycling a tank. Cycling a tank, which is the natural buildup of beneficial bacteria that does the job of breaking down ammonia and nitrites, usually takes about six to eight weeks. Decaying food, fish waste and plant particles break down and form ammonia, which in turn decomposes into nitrites (in the presence of the beneficial bacteria) and then into nitrates. The conversion of nitrites to nitrates takes some time, so a build up of nitrites can occur. The presence of nitrites makes it harder for the fish to receive oxygen from the water. Heavy breathing is often a sign of high levels of nitrites. Ammonia, nitrite and nitrate levels can quickly spike to very high levels in a very short period of time, as short as a day or two depending on the number fish per gallon of water and other conditions.
While ammonia and nitrites can kill Tropheus quickly, nitrates do not have the same effect. The only real problem that can occur with nitrates is that it is suspected that extended exposure to high levels of nitrates can cause problems in breeding.
So what can and should be done?
If you are starting your very first tank, you should go slowly. If possible, start with a small number of fish until the tank has cycled. This will result in smaller peaks of ammonia and nitrites, which will be less harmful to the fish. Later, it will be much safer to add additional fish. Watch the levels of ammonia and nitrite very closely, even daily for the first few weeks or longer depending on your results, and then perhaps every other day for the next two weeks. If you see them increasing sharply, do an immediate water change of about 20-25%, no more. You will probably have to do this daily for about a week, possibly more. The reason you shouldn't remove more than 25% of the water is that you would take out too much of the beneficial bacteria and the tank wouldn't cycle as fast. You also run a risk of “shocking”** the fish if you change too much water. For the first few months of a new tank you should not do any larger of water changes than 25% to make sure the beneficial bacteria are not depleted. We have found that 50% water changes do more harm than good*, because the tanks are continuously cycling and the beneficial bacteria never have a chance to get a sufficient size colony.
If you have another tank, you can "borrow" some beneficial bacteria from the established tank. You can borrow a sponge filter, (most any kind of filter), a bio-wheel, gravel or any other matter than contains the beneficial bacteria.
Even adding a portion of water from an existing healthy tank to the new tank is helpful.
If you are reestablishing an existing tank, try to keep some of the biological life, (beneficial bacteria), alive from the old tank. It could be an old sponge filter, an old bio-wheel, or even some original gravel or water from the old tank, if healthy. Simply keep immersed in the original tank water, preferably with some sort of aeration going, which can be as simple as an air stone, which helps keep oxygen available to the bacteria to help keep it alive.
Be careful of how much you feed your fish in a new or reestablished tank. Excess food is one of the biggest contributors to ammonia in a tank.
Decomposing food creates a nasty mess and is so easy to avoid. Light feedings for the first weeks is a good rule to follow, and gradually increasing to normal feedings in about three weeks or so.
Regardless of whether you are setting up a new tank or reestablishing one, you should get as much oxygen as possible in the tank. An air venturi on a powerhead works very well in this case. Anything, which will create further turbulence to the surface water, will help increase the oxygen in the water up to it's holding capacity. The additional oxygen helps the bacteria grow and it is also helpful to the fish, particularly should any bad conditions exist.
When doing a water change on a tank, we prefer to "spray" the fresh water back into the tank. This tends to release the chlorine from the water and helps oxygenate the water as well.
The addition of salt* to a tank seems to lessen the effects of ammonia and nitrite poisoning. It does not remove these compounds, but can help the fish cope with the stress of having less than ideal water quality.
*Non-iodized, as recommended on container if using salt specifically made for fish.
If you live in an area in where your water supply is treated with chloramines, you need to be extra careful with water changes and cycling a tank. Chloramines are a compound of chlorine and ammonia. When you break the bond between these, you release the harmful chlorine out of the water, but the ammonia remains behind. There are commercial compounds that also lock the ammonia in a harmless compound, but some do not. When using de-chlorinators, it is sometimes necessary to use as much as triple of the amount recommended to have the desired result. The larger problem is that most test kits will not detect the trapped ammonia.
You have to buy a special kit to test the water. Unfortunately, the left over ammonia can break down and cause problems. You need to be able to test for them. Smaller but more frequent water changes may be the best route to deal with chloramines. Be sure and check with your local municipalities to see what is added to your water supply.
We recommend using a de-chlorinator that contains "slime" for lack of a better word. There is one de-chlorinator that we have used that does not work and will kill your fish at some point. It traps the ammonia, which is then released later. As you cycle through a tank and are doing a daily water changes, the result is a disaster.
There is no reason to be afraid to set up a new tank or reestablish an existing one if you follow some simple rules. Keeping a close eye on the water conditions and acting accordingly will result in a healthy, happy tank.
I hope this information is of benefit to you. The suggestions in this article are not the result of scientific tests, but are the results of our experiences in keeping Tropheus. □