Why do some Bicolor Hammer heads lose the two-tone look over time?

Shifts in spectrum and nutrients can favor one pigment. Keep moderate PAR (80–150), strong blue/violet (420–450 nm), and stable nutrients (nitrate 5–15 ppm, phosphate 0.03–0.10 ppm). Avoid ultra-low nutrients and excessive white light. Pigment can rebound over weeks; if one branch stays monotone, fragging and placing it in slightly lower light can help restore contrast.

My Fimbriaphyllia paraancora is receding from the base up—what’s the likely cause?

Base-up recession often points to bacterial issues or tissue damage at the skeleton edge, not just alkalinity swings. Inspect for dead skeleton or detritus accumulation. Increase random flow, turkey-baste debris, and perform an antiseptic dip (iodine-based). If a head is collapsing, cut it off above the rot to protect healthy branches. Maintain stable alk 8–9.5 dKH and mag 1300–1400 ppm.

How far can its sweeper tentacles reach, and does it tolerate other Euphyllia?

Night sweepers commonly reach 2–3 inches, sometimes more in strong current. Give 4–6 inches of clearance. It may coexist with other hammers of the same colony better than with frogspawn or torch corals, which can provoke chemical and bacterial skirmishes. Avoid direct contact between different species or morphs, and run carbon with regular changes to reduce allelopathic stress.

How do I prevent Brown Jelly Disease after a head is damaged?

Act fast: siphon the jelly, perform an antiseptic dip, increase aeration and random flow, and remove the affected head above healthy tissue. Keep nutrients stable, reduce heavy feeding, and maintain clean but not sterile water. Replace or rinse mechanical filtration, run fresh carbon, and avoid sudden light increases during recovery to limit further stress.

Bicolor Hammer Coral

Hammer

Overview

The Bicolor Hammer Coral shows contrasting tips on hammer-shaped tentacles. Fimbriaphyllia paraancora is a large-polyp stony coral with branching heads, favoring moderate light and gentle to moderate flow. It relies on symbiotic algae for most nutrition, and occasional meaty foods can support growth and maintain color. Place with space from neighbors; sweeper tentacles can sting nearby corals.

Quick Facts

Care Moderate

Lighting Moderate

Flow Moderate, indirect

Placement Mid–Low

Temperament Aggressive (6–8 inches spacing)

Recommended Parameters

Temp 77–80°F

pH 8.1–8.4

Salinity 1.025–1.026

Calcium 400–450 ppm

AlkAlkalinity 8–9.5 dKH

Magnesium 1280–1350 ppm

Feeding photosynthetic, mysis shrimp, enriched brine shrimp, finely chopped seafood (shrimp, clam), copepods, rotifers, zooplankton, LPS coral foods

Care & Placement

Bicolor Hammer Coral (Fimbriaphyllia paraancora) thrives with stable, moderate conditions. Provide medium light (80–150 PAR) and gentle, indirect flow that keeps polyps swaying without blasting the tissue; this helps prevent detritus buildup and tissue damage. Place low to mid in the tank on a stable, rounded surface with room to expand. Keep 6–8 inches from other corals; sweeper tentacles can extend several inches at night and sting neighbors. It can coexist with conspecifics if healthy and pest‑free, but mixing with other Euphyllia types is risky. Feed primarily via light; supplement 1–2x weekly with small meaty foods (mysis, brine, finely chopped seafood) or fine particulate coral foods. Avoid overfeeding to keep nutrients in check. Target water parameters: 76–80°F, pH 8.1–8.4, salinity 1.025–1.026, alkalinity 8–9.5 dKH, calcium 420–460 ppm, magnesium 1300–1400 ppm, nitrate 2–10 ppm, phosphate 0.02–0.08 ppm. Test weekly and prioritize stability, as this coral is sensitive to rapid swings, especially in salinity and alkalinity.Acclimate with a 30–45 minute drip and light acclimation (reduced intensity or screen) to avoid bleaching. Handle by the skeleton, not the fleshy heads. Signs of trouble: pale tissue (excess light or low nutrients), recession (alk swings or too little flow), droopy or retracted polyps (flow imbalance or low magnesium). Watch for brown jelly disease after damage; promptly siphon, iodine dip, and increase flow around the colony. Consider dosing calcium/alkalinity as growth increases, and keep flow adjustable to match polyp extension over time.

FAQ

Frequently Asked Questions

About the Bicolor Hammer Coral

Why do some Bicolor Hammer heads lose the two-tone look over time?

Shifts in spectrum and nutrients can favor one pigment. Keep moderate PAR (80–150), strong blue/violet (420–450 nm), and stable nutrients (nitrate 5–15 ppm, phosphate 0.03–0.10 ppm). Avoid ultra-low nutrients and excessive white light. Pigment can rebound over weeks; if one branch stays monotone, fragging and placing it in slightly lower light can help restore contrast.
My Fimbriaphyllia paraancora is receding from the base up—what’s the likely cause?

Base-up recession often points to bacterial issues or tissue damage at the skeleton edge, not just alkalinity swings. Inspect for dead skeleton or detritus accumulation. Increase random flow, turkey-baste debris, and perform an antiseptic dip (iodine-based). If a head is collapsing, cut it off above the rot to protect healthy branches. Maintain stable alk 8–9.5 dKH and mag 1300–1400 ppm.
How far can its sweeper tentacles reach, and does it tolerate other Euphyllia?

Night sweepers commonly reach 2–3 inches, sometimes more in strong current. Give 4–6 inches of clearance. It may coexist with other hammers of the same colony better than with frogspawn or torch corals, which can provoke chemical and bacterial skirmishes. Avoid direct contact between different species or morphs, and run carbon with regular changes to reduce allelopathic stress.
How do I prevent Brown Jelly Disease after a head is damaged?

Act fast: siphon the jelly, perform an antiseptic dip, increase aeration and random flow, and remove the affected head above healthy tissue. Keep nutrients stable, reduce heavy feeding, and maintain clean but not sterile water. Replace or rinse mechanical filtration, run fresh carbon, and avoid sudden light increases during recovery to limit further stress.

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Bicolor Hammer Coral

Overview

Quick Facts

Recommended Parameters

Care & Placement

Hammers