What are the symptoms of Marine Ich?

Fine white nodules 0.5-1 mm across the body and fins, like sprinkled salt; Heavy flashing against live rock, sand or glass, sometimes to the point of injury; Rapid breathing with flared gill covers, often holding position in strong flow; Reduced appetite and hiding, with cloudiness or a white film around the eyes and gills. It usually starts with: Tomonts arriving on new fish, live rock or corals without quarantine; Outbreaks after temperature or salinity swings and the stress of moving; Overcrowding and elevated ammonia weakening the slime barrier.

How do you treat Marine Ich?

In order: 1. Move every fish into a hospital tank (Marine ich can only be treated in a hospital tank: the display tank must be emptied of all fish, while invertebrates, corals and live rock stay behind, because copper and formalin would wipe out the invertebrates.) 2. Chelated copper at 0.15-0.25 mg/L in the hospital tank (Hold free copper at 0.15-0.25 mg/L using a copper test kit for 14-30 days, never letting the level drift out of the therapeutic window - too low is ineffective, too high poisons the fish. Copper is lethal to corals, shrimp, snails, starfish and live rock life, so it must be used in the hospital tank only.) 3. Or use hyposalinity at 1.009 for at least 30 days (The alternative is to lower hospital tank salinity slowly to 1.009 and hold it for more than 30 days, checking daily with a hydrometer or refractometer. A reef tank cannot be hyposalinated, so copper is the only route there. Do not combine the two methods.) 4. Leave the display tank fallow for 76 days (Once every fish is out, keep the display tank fallow for 76 days before returning the first fish. That figure conservatively covers the longest tomont survival at lower temperatures, and shortening it puts the disease straight back.) 5. Confirm the full course before returning fish (Finish the entire course even after the spots disappear, and drip-acclimate the fish for 1-2 hours before returning them; cutting a copper course short almost guarantees a relapse.)

What medication treats Marine Ich?

Chelated copper: Hospital tank only, holding 0.15-0.25 mg/L with a copper test kit for 14-30 days. Copper is lethal to corals, shrimp, snails, starfish and live rock life, so it must be dosed in a hospital tank; never combine it with formalin.; Copper sulfate: Cheaper but with a narrower therapeutic window, requiring frequent copper testing; hospital tank only. It is lethal to invertebrates, and a slight overdose kills the fish outright.; Chloroquine phosphate: An alternative available in some markets, used at the label dose in a hospital tank only, kept out of light and with attention to invertebrate toxicity; purity varies between sources, so prefer copper or hyposalinity if unsure.

G-04 / 14Marine

Marine Ich海水白点

Very urgent. Marine ich can kill a whole tank within days, and only hospital-tank treatment plus a 76-day fallow period actually breaks the cycle - dosing the display tank alone will not work.

Illustration to come

G-04 / 14 · Marine Ich

SpecificationsDisease atlas

Cause: Parasite
Severity: Severe
Contagion: Highly contagious
Corals / inverts: Not safe
Also known as: Cryptocaryon irritans、Marine white spot

Symptoms

Fine white nodules 0.5-1 mm across the body and fins, like sprinkled salt
Heavy flashing against live rock, sand or glass, sometimes to the point of injury
Rapid breathing with flared gill covers, often holding position in strong flow
Reduced appetite and hiding, with cloudiness or a white film around the eyes and gills

Typical triggers

— Tomonts arriving on new fish, live rock or corals without quarantine
— Outbreaks after temperature or salinity swings and the stress of moving
— Overcrowding and elevated ammonia weakening the slime barrier

Treatment, in order

1 · IsolateMove every fish into a hospital tankMarine ich can only be treated in a hospital tank: the display tank must be emptied of all fish, while invertebrates, corals and live rock stay behind, because copper and formalin would wipe out the invertebrates.
2 · MedicationChelated copper at 0.15-0.25 mg/L in the hospital tankHold free copper at 0.15-0.25 mg/L using a copper test kit for 14-30 days, never letting the level drift out of the therapeutic window - too low is ineffective, too high poisons the fish. Copper is lethal to corals, shrimp, snails, starfish and live rock life, so it must be used in the hospital tank only.
3 · SaltOr use hyposalinity at 1.009 for at least 30 daysThe alternative is to lower hospital tank salinity slowly to 1.009 and hold it for more than 30 days, checking daily with a hydrometer or refractometer. A reef tank cannot be hyposalinated, so copper is the only route there. Do not combine the two methods.
4 · Water changeLeave the display tank fallow for 76 daysOnce every fish is out, keep the display tank fallow for 76 days before returning the first fish. That figure conservatively covers the longest tomont survival at lower temperatures, and shortening it puts the disease straight back.
5 · ObserveConfirm the full course before returning fishFinish the entire course even after the spots disappear, and drip-acclimate the fish for 1-2 hours before returning them; cutting a copper course short almost guarantees a relapse.

The standard treatment uses copper or formalin, which is lethal to corals, shrimp, snails and everything on live rock. Treat in a quarantine tank only, and leave the display tank fallow for the full period above before returning the fish.

Medications and cautions

Chelated copper: Hospital tank only, holding 0.15-0.25 mg/L with a copper test kit for 14-30 days. Copper is lethal to corals, shrimp, snails, starfish and live rock life, so it must be dosed in a hospital tank; never combine it with formalin.
Copper sulfate: Cheaper but with a narrower therapeutic window, requiring frequent copper testing; hospital tank only. It is lethal to invertebrates, and a slight overdose kills the fish outright.
Chloroquine phosphate: An alternative available in some markets, used at the label dose in a hospital tank only, kept out of light and with attention to invertebrate toxicity; purity varies between sources, so prefer copper or hyposalinity if unsure.

Prevention

Quarantine all new fish for at least 4 weeks before adding them to the display tank
Rest corals and live rock separately from fish so tomonts are not carried in with the water
Do not share nets or buckets between the display and quarantine tanks
Keep temperature and salinity stable to reduce stress-triggered outbreaks

Frequently asked questions

What are the symptoms of Marine Ich?: Fine white nodules 0.5-1 mm across the body and fins, like sprinkled salt; Heavy flashing against live rock, sand or glass, sometimes to the point of injury; Rapid breathing with flared gill covers, often holding position in strong flow; Reduced appetite and hiding, with cloudiness or a white film around the eyes and gills. It usually starts with: Tomonts arriving on new fish, live rock or corals without quarantine; Outbreaks after temperature or salinity swings and the stress of moving; Overcrowding and elevated ammonia weakening the slime barrier.
How do you treat Marine Ich?: In order: 1. Move every fish into a hospital tank (Marine ich can only be treated in a hospital tank: the display tank must be emptied of all fish, while invertebrates, corals and live rock stay behind, because copper and formalin would wipe out the invertebrates.) 2. Chelated copper at 0.15-0.25 mg/L in the hospital tank (Hold free copper at 0.15-0.25 mg/L using a copper test kit for 14-30 days, never letting the level drift out of the therapeutic window - too low is ineffective, too high poisons the fish. Copper is lethal to corals, shrimp, snails, starfish and live rock life, so it must be used in the hospital tank only.) 3. Or use hyposalinity at 1.009 for at least 30 days (The alternative is to lower hospital tank salinity slowly to 1.009 and hold it for more than 30 days, checking daily with a hydrometer or refractometer. A reef tank cannot be hyposalinated, so copper is the only route there. Do not combine the two methods.) 4. Leave the display tank fallow for 76 days (Once every fish is out, keep the display tank fallow for 76 days before returning the first fish. That figure conservatively covers the longest tomont survival at lower temperatures, and shortening it puts the disease straight back.) 5. Confirm the full course before returning fish (Finish the entire course even after the spots disappear, and drip-acclimate the fish for 1-2 hours before returning them; cutting a copper course short almost guarantees a relapse.)
Is Marine Ich contagious, and how urgent is it?: Contagion: highly contagious. Severity: severe. Cause: parasite. Very urgent. Marine ich can kill a whole tank within days, and only hospital-tank treatment plus a 76-day fallow period actually breaks the cycle - dosing the display tank alone will not work.
What medication treats Marine Ich?: Chelated copper: Hospital tank only, holding 0.15-0.25 mg/L with a copper test kit for 14-30 days. Copper is lethal to corals, shrimp, snails, starfish and live rock life, so it must be dosed in a hospital tank; never combine it with formalin.; Copper sulfate: Cheaper but with a narrower therapeutic window, requiring frequent copper testing; hospital tank only. It is lethal to invertebrates, and a slight overdose kills the fish outright.; Chloroquine phosphate: An alternative available in some markets, used at the label dose in a hospital tank only, kept out of light and with attention to invertebrate toxicity; purity varies between sources, so prefer copper or hyposalinity if unsure.
Is the treatment for Marine Ich safe for corals and inverts?: No. The standard treatment (copper or formalin based) is lethal to corals, shrimp, snails and everything on live rock. Treat in a quarantine tank only, and leave the display tank fallow for the full period given above.