Green and Blue Stem Hammer

Green and Blue Stem Hammer is a hammer coral with broad, hammer-shaped polyp tips and flowing tissue. Its movement and coloration are best displayed when the coral is given stable reef conditions, suitable light, and gentle indirect water movement.

Hammer Coral Care

Hammer corals respond best to stable reef conditions. Place this coral where its fleshy polyps can sway without being folded over or driven against the skeleton by a direct stream. Acclimate it gradually to your lighting and leave open space around the colony for nighttime sweeper tentacles.

Placement and Acclimation

Branching hammer corals grow as separate heads on a branching skeleton; protect the soft tissue from abrasion when handling or positioning the frag. Start at the lower end of the stated light range, then adjust gradually while watching polyp extension and tissue condition. Keep the coral separated from neighbors that could be reached by its sweepers.

Maintain consistent salinity and alkalinity, and avoid sudden changes in light or flow. Do not force food into retracted polyps; stable conditions and appropriate placement matter more than heavy feeding.

What to expect when it arrives

Open the box the day it lands. A shipped Euphyllia arrives retracted, often with the tentacles pulled almost completely into the skeleton, and it can look alarming if you have not seen it before. That is normal. Float the sealed bag for 15 minutes to match temperature, then drip acclimate over 45 to 60 minutes. Do not add the shipping water to your tank.

Give it a low-flow, moderate-light spot on the first day and leave it there. Most torches and hammers begin partial extension within 24 hours and are fully open in one to three days. The single most common mistake is deciding after six hours that the spot is wrong and moving it — every move restarts the adjustment clock, and a coral moved four times in a week may never settle.

Placement, once it has opened

Watch the tentacle behavior rather than the PAR number. Tentacles should drift and sway with a slow rhythm. If they stream in one direction and stay there, flow is too strong. If they hang limp and short with the coral inflated, flow may be too weak. Adjust one variable at a time and give it three days between changes.

Allow six inches of clear space in every direction before you commit to a location. Euphyllia sweeper tentacles extend well beyond the daytime footprint after lights out, and the neighbor that looks safe at noon may be getting burned at 2 a.m. If you keep other Euphyllia, they generally tolerate each other, but torches will win any exchange.

Growth and fragging

A settled Euphyllia adds heads by splitting, and in a stable tank with occasional feeding you should see a head begin to divide within three to six months. Branching forms separate onto their own stalks and can be cut apart cleanly once the branch has elongated; wall forms are harder to divide and most keepers leave them whole. A colony that has not split in a year is usually reporting a flow or light problem rather than bad genetics.

Tank mates and compatibility

Keep it away from any coral it can reach. Peaceful fish are fine, but large angels, some butterflies and a few wrasses will pick at Euphyllia tentacles, and a coral that retracts every time a specific fish passes is telling you something. Clownfish will sometimes host in a torch; this is usually tolerated but can damage the tissue over months.