protozoan · saltwater tank

Brown Jelly Disease (LPS coral)

Brown jelly disease is a fast-spreading infection of LPS coral (especially Euphyllia, frogspawn, hammer, torch) characterized by a brown gelatinous mucus that consumes tissue within 48-72 hours.

Reviewed by the Fast Aquatics husbandry team · Updated May 2026
Severity: CRITICAL - can spread to entire LPS collection within days

Symptoms to look for

What causes it

Often triggered by stress (parameter swing, alkalinity drop, low DO) followed by protozoan infection. Spreads rapidly between LPS pieces.

Treatment options

Multiple effective treatments exist. Pick based on your tank type, livestock sensitivity, and severity. Always treat in a separate quarantine/hospital tank - most medications are toxic to coral, invertebrates, and live rock biology.

Frag healthy tissue. Remove the coral, cut healthy tissue away from the necrotic edge with sharp shears, dip in CoralRx or Bayer for 5 minutes, mount on a clean plug, return to moderate flow.
Iodine dip + flow. For early-stage: dip the affected piece in Lugol's iodine (4 drops per gallon of saltwater) for 5 minutes, then return to a high-flow area. Iodine is mildly antimicrobial.
Increase flow + lights. Once stabilized, place coral in higher-flow areas. Brown jelly thrives in low-flow stagnation.

Prevention

Stable parameters (alk swing <0.5 dKH/24hr), good flow on all LPS, dip every new coral, isolate any coral showing symptoms immediately.

Frequently asked questions

What does Brown Jelly Disease (LPS coral) look like?

Brown jelly-like substance on the coral. Tissue receding from skeleton. Coral failing to extend polyps.

What causes Brown Jelly Disease (LPS coral)?

Often triggered by stress (parameter swing, alkalinity drop, low DO) followed by protozoan infection. Spreads rapidly between LPS pieces.

How is Brown Jelly Disease (LPS coral) treated?

Frag healthy tissue: Remove the coral, cut healthy tissue away from the necrotic edge with sharp shears, dip in CoralRx or Bayer for 5 minutes, mount on a clean plug, return to moderate flow.

Can Brown Jelly Disease (LPS coral) be prevented?

Stable parameters (alk swing <0.5 dKH/24hr), good flow on all LPS, dip every new coral, isolate any coral showing symptoms immediately.

How fatal is Brown Jelly Disease (LPS coral)?

CRITICAL - can spread to entire LPS collection within days

Should I treat in the display tank or quarantine?

Always treat in a separate quarantine or hospital tank. Most medications are toxic to coral, invertebrates, and live rock biology.

Related

Browse the full disease database for 45 aquarium conditions with treatment protocols, or check the care library for prevention-focused husbandry guides. Use our symptom matcher to rank likely diseases from observed signs, the water parameter checker to diagnose related water-quality issues, or the QT timeline calculator to plan a treatment schedule.