I got a 20 gallon tank and the filter has been running for almost two weeks. Fri...
Yes, a small number of fish can be added to your aquarium now.
The Stress Zyme will seed the aquarium with the beneficial bacteria that are needed to break down the fish waste from toxic ammonia into nontoxic components, but unless there are fish there creating some waste, the bacteria can only grow so much.
The fish need to be added over a period of time. We recommend adding about 3 fish per week, until the tank capacity is reached. About 6-12 fish in a 20 gallon aquarium, depending on the size of the fish, is appropriate.
Add the Stress Zyme the day you are adding your new fish. Then be sure to monitor the water quality weekly. Do not add more fish if there is an increase in ammonia or nitrite in the water.
Ask for the Care Guides on setting up an aquarium and on general fish care at the PetSmart store. These explain the nitrogen cycle process that occurs in new aquariums. Knowing this will help prevent disasters from loading the aquarium with too many fish too soon.