How long should you wait to put fish in a new tank?
How long should you wait to put fish in a new tank? Adding Fish to a Brand-New Tank Typically, you should wait at least 24 to 48 hours and even up to a week before adding fish to a new tank. Waiting ensures that all the set conditions for the ecosystem have had time to establish themselves. This also gives your fish enough time to acclimate to their new environment.