Step-by-step
Step 1: Float the bagFloat the sealed shipping bag in your tank for 15 minutes to equalize temperature within ±1°F. DO NOT open the bag yet - the high CO2 in shipping water keeps ammonia non-toxic; opening it instantly converts ammonia to its toxic form.
Step 2: Open and pour into containerOpen the bag and gently transfer fish + shipping water into a clean container at the side of the tank. Do this quickly to minimize air exposure.
Step 3: Set up drip lineRun air-line tubing from your display, knot or use a drip valve to slow flow to 2-3 drops per second. Start the siphon by mouth (rinse out before doing this!) or with a turkey baster.
Step 4: Drip until volume triplesAllow display water to drip into the acclimation container until original shipping water volume has tripled (saltwater) or doubled (freshwater). Takes 60-90 minutes. Bail off excess if container overflows.
Step 5: Verify parameters matchSaltwater: refractometer reading should match display ±0.001 SG. Freshwater: TDS or hardness should match display.
Step 6: Net into displayNet the fish - never pour shipping water into the tank (it carries pathogens and ammonia). Discard acclimation water down the drain.
Step 7: Lights off observationKeep tank lights low or off for the first 4-8 hours. Resist the urge to feed for 24 hours so fish settles without digestive stress.
Frequently asked questions
How long should I acclimate a new fish?
60-90 minutes for drip acclimation. Float-only (15 minutes) is risky for sensitive species. Less than 30 minutes virtually guarantees parameter shock for marine fish.
Do I need to drip acclimate freshwater fish?
Yes for invertebrates (sensitive to TDS swings). Optional for hardy freshwater fish but always drip if shipping was multi-day.
What if the fish look stressed during acclimation?
Slow the drip and watch closely. If gasping or laying on side, complete acclimation faster (transfer at 2x volume instead of 3x) - parameter mismatch is killing them slower than the stress of a faster transfer.