Coral care guide
How to Acclimate New Coral
Good coral acclimation is a controlled handoff between two systems. The goal is to limit temperature, salinity, lighting and handling stress while preventing shipping water and hitchhikers from entering the display.
Acclimation should be deliberate, not an obstacle course that keeps a stressed coral in a bag for another two hours.
Before the coral arrives
Prepare a clean inspection area, white light, gloves, eye protection, separate containers, coral-safe tools and the quarantine or dip products you already intend to use. Confirm the aquarium’s temperature and salinity before opening the shipment.
Read the seller’s arrival and guarantee instructions first. Photograph any obvious issue while the coral is still sealed when the policy requires it.
A practical acclimation sequence
- Inspect the sealed bag. Confirm the coral, note water temperature and photograph damage or severe stress.
- Equalize temperature conservatively. Avoid leaving a shipping bag under hot aquarium lights or floating it longer than necessary.
- Move the coral to a clean container. Keep shipping water separate from the display and quarantine systems.
- Inspect under white light. Check tissue, skeleton, plug, underside, eggs, pests and nuisance algae.
- Address salinity differences. Follow the seller’s guidance and avoid unnecessarily prolonged exposure to opened shipping water.
- Dip only with an appropriate product. Follow the current label exactly; never mix dips or assume stronger is safer.
- Rinse in clean system water. Use a separate container and discard shipping, dip and rinse water.
- Place in quarantine or an acclimation location. Begin with conservative light and coral-appropriate flow.
Temperature and salinity
Rapid temperature or salinity changes add avoidable stress. Measure rather than guessing, but do not stretch acclimation indefinitely while opened shipping water changes chemistry.
There is no single drip-acclimation schedule appropriate for every coral and every shipment. Follow species-appropriate seller instructions, account for the actual salinity difference and minimize time in degraded shipping water.
Inspection, dipping and quarantine
A dip is not a complete quarantine program. Many products affect mobile pests but do not reliably kill eggs, and no dip makes visual inspection unnecessary.
- Inspect the top, sides, plug and underside under white light.
- Remove dead material or nuisance algae only when it can be done without damaging living tissue.
- Use separate containers and tools for shipping water, dip and rinse water.
- Never combine dip products or exceed label concentration and duration.
- Observe the coral in quarantine long enough to catch pests that were hidden or newly hatched.
Zoanthids require additional handling precautions because some colonies may contain palytoxin. Read our Zoanthid Coral Care Guide before cutting or cleaning them.
Light acclimation
Shipping darkness does not mean a coral should be placed immediately at its final peak PAR. Begin at the conservative end of the appropriate range and increase exposure gradually.
Adjust intensity, placement or photoperiod in planned steps. Change one variable at a time and watch tissue inflation, polyp extension and color. A light meter is useful, but the coral’s response still matters.
For demanding SPS, read our SPS & Acropora Coral Care Guide. For fleshy LPS, protect expanded tissue from sharp rock while choosing a lower-light starting point.
Flow acclimation
Flow should keep the coral clean without pinning tissue against the skeleton or lifting the frag from its mount. Start with indirect movement appropriate to the coral group.
Watch the animal rather than the pump percentage. A Torch should sway without snapping. Zoanthid skirts should move gently. An Acropora should receive strong, varied flow without one branch taking the entire stream.
The first week
The first week is for stability and observation.
- Keep placement consistent unless there is a clear problem.
- Verify temperature and salinity daily after unusual shipping stress.
- Inspect for pests and tissue changes under white light.
- Avoid heavy feeding until the coral shows a normal response.
- Do not chase temporary color changes with immediate dosing.
- Photograph the coral in the same lighting to compare the direction of change.
Some corals open within hours; others take several days. Look for improvement rather than demanding a fixed timetable from every species.
When to intervene
Act promptly when you see rapid tissue loss, brown gelatinous material, a widening band of exposed skeleton, severe bleaching, a strong odor or confirmed pests. Isolate the coral when practical and avoid sharing contaminated tools or water.
A coral that is simply less inflated after shipping often benefits from stable placement and reduced handling. Intervention should match an observed problem.
Final take
Inspect first, keep shipping water out of the system, use an appropriate quarantine process and acclimate light and flow gradually. The safest new-coral routine is repeatable enough that excitement does not redesign it every delivery day.