Introducing a new fish to your aquarium does not need to be difficult. Most of them that are commercially available have already been moved a number of times in their lives and are adept at quickly adapting to a new environment. Before the process of introducing a new fish even begins, one must research a fish’s natural environment. Only if this environment is in line with the conditions in your tank can the introduction be successful. There is no amount of preparation that will enable one to live outside its preferred temperature range or lighting conditions.
Freshwater fish tank fish require the least amount of time for acclimation. When adding them to a tank that already contains a number of fish, one must simply allow the bag in which they are transported to float for 10-20 minutes in your tank’s water. This will enable them to gradually adjust to the ambient temperature of the tank and avoid drastic temperature changes that could be potentially harmful. As the fish will be floating near the top of the tank, be sure to turn off tank lights to avoid heating the bag and reduce the amount of stress on the fish.
After the water within the bag has had a few minutes to adjust, begin adding small amounts of aquarium water to the bag in which your tropical fish is swimming. Each addition should be followed by more adjustment time. This will give the fish time to get used to the water quality of a tank. Another 10-15 minutes or so and the fish will be ready to be introduced to the tank and the rest of the fish population.
Do not dump the bag containing the fish tank tropical fish into an aquarium. The fish should be removed from the bag with a net designed for this purpose, and quickly deposited into the tank. The water in the bag should be discarded to avoid affecting the water quality of the tank.
Salt water fish tank fish can be introduced with the same methods, but the amount of time they are allowed for acclimation should be much longer. When adding water to the bag in which they were transported, the water should be added very gradually. They should be given as much as an hour to adjust to each addition. Through this may seem painstaking, it is vital to ensuring a successful transition.
Be wary of adding too many new fish at a time. Beginners should only add two or three fish every few weeks to maintain tank stability and fish health.