Posted by @Chris_Lewis · 1h ago
New fish arrive in water that is a different temperature and chemistry from your tank. Dumping them straight in shocks them; a few minutes of acclimation dramatically improves survival.
Float first (temperature). Float the sealed bag in your tank for about 15 minutes so temperatures equalize. Do not open it yet.
Then equalize chemistry. Two common methods:
- Float-and-add: open the bag and every few minutes add a small scoop of tank water, over ~15–20 minutes, so pH and hardness shift gradually.
- Drip method (gentler — best for sensitive fish, shrimp, and all marine livestock): put the fish and bag water in a container and run a slow airline-tube siphon drip from the tank, a drip or two per second, until the volume roughly doubles or triples.
Net the fish into the tank — do not pour the bag water in. Store water can carry ammonia, medication, or disease. Discard it.
Lights off for a few hours afterward, and skip feeding that first day.
One step better: quarantine new arrivals in a separate tank before they ever meet your display — the best disease-prevention habit in the hobby.
Your turn: what is your acclimation routine, and have you had losses you suspect were acclimation-related? Walk us through it.