Maintaining good water quality is the single most important thing that you can do to ensure the health of your fish. A partial
water change, no more than 25% at a time, is the solution. Doing a change every 1-2 weeks, or more often when needed, removes decaying matter, reduces nitrate build-up, replaces trace elements, and makes more oxygen available to fish.
Put your replacement water to the test
Test your source water before you add it to the aquarium. You need to be aware of its hardness and pH. If it is out of desirable range, you will need to
condition it to bring it into acceptable levels. Also, test for chlorine and chloramines that are added by many municipal water departments. If present, they can be removed by adding
water conditioners such as
Amquel. And to avoid stressing your fish, always be sure to balance the
temperature of your input water with your aquarium water.
Weekly is better
Never allow water quality to decline to such degree that a large change is necessary. Preforming infrequent water changes of more than 25% at one time can put beneficial bacteria levels out of balance and alter pH enough to shock fish. In general, it is better to do regular small water changes - around 10% - to maintain water parameters within acceptable levels. Water conditions will steadily deteriorate by "putting off" water changes longer than a month.
Don't forget filter maintenance
Be sure to replace your
chemical media on a regular basis. If mechanical media becomes clogged, it also becomes less efficient and slows water flow. Chemical media like carbon, once it reaches saturation, may in fact leach back into the water the very toxins you wanted to remove from your aquarium. Finally, clean your filter plumbing and pump impeller every month or so to ensure maximum efficiency. Buildup inside tubing may reduce water flow by 30% or more, meaning less water moving past your bio media and more ammonia accumulation!