How to Acclimate Corals and Fish

Fish: drip acclimation

Bulk Reef Supply’s nine-step method, condensed.

• Dim the lights and check every fish is alive
• Float the sealed bags for at least 20 minutes, longer if the water was very cold
• Cut the bags open into a small bucket
• Drip tank water in at about 2–4 drops a second, or add half a cup every 5 minutes
• When the volume doubles, pour half away, then keep dripping
• Stop once it has doubled twice: about 20–45 minutes
• Net the fish across; never pour the bucket water into the tank
• Top up the tank with clean saltwater if needed
• Keep the lights off until the next day

Corals: float and dip

Bulk Reef Supply says shops usually show you how to float the bag for temperature, and drip acclimation is a slower option. Dipping is a separate step to remove pests: 5–10 minutes in a coral dip, then rinse in tank water before placing.

Place new corals lower and out of the strongest light and flow at first. A jump to bright light can bleach them; see coral turning white.

Quarantine first

Acclimation gets livestock safely into water. Quarantine keeps disease out of your display. See quarantine for marine fish.

Write it down

Note the date and what you added. If something changes in the following week, you’ll know what was new.

How long should I acclimate a fish?

Bulk Reef Supply’s drip method takes about 20–45 minutes after floating for temperature.

Do corals need drip acclimating?

Floating for temperature is usually enough; dripping is a gentler option. Dip for pests either way.

Can I pour the bag water in?

No. Bulk Reef Supply says never add bag water to your tank.