Avoiding Contamination in Aquarium
Prevention of contamination of your aquarium includes interruption of cross-contamination between the aquarium and tanks. To prevent this, when buying a new fish, do not empty the water that is delivered with the fish inside the aquarium.
No cleaning agents
Virtually all cleaning agents are lethal to fish. Soaps, bleach, ammonia, should be kept away from working surfaces and aquarium equipment. Chances are the work area will be either the laundry tub or the bathtub. Both areas will be contaminated with a variety of toxins which can be transferred to water changing and cleaning equipment. Rinse everything before starting and before the items are put away. Special cleaning should be applied to equipment dropped onto contaminated surfaces.
Hands come into contact with many substances which should not be introduced into the aquarium. Wash hands in the hottest water reasonable. DO NOT USE SOAP! Use a mild scrub brush on hands and a fingernail brush for extra caution. Make sure the brushes are never used with any cleaning agents.
Designate equipment for aquarium use only
All equipment used for the aquarium should never be used for any other purpose. There is no guarantee that contaminants can be adequately removed. Buy two or three five gallon buckets from Home Depot or Menards and label them in big black marker: Aquarium Use ONLY. These can be used to change water as well as establishing a “safe zone” to hold cleaning equipment, filter components, and aquarium decorations during cleaning.
Avoiding Biological Contamination
If more than one aquarium is present in the household, care should be taken to avoid contamination from one tank to another. Allow all equipment (including hands) to thoroughly dry before using in another aquarium. Nets which can stay wet for days are a special case. These items can be soaked in a strong salt solution between uses to kill any pathogens. Care should be taken not to soak the nets for more than a few minutes as the salt solution will quickly rust any metal parts in the net. Hard plastic items can be soaked for a few minutes in a weak solution of bleach. Make sure that the item is thoroughly rinsed before using again. If the item smells even mildly of bleach it MUST be rinsed again. Even a small amount of bleach will kill fish.