Blastomussa Corals

What are Blastomussa corals?

Blastomussa are large polyp stony corals that grow as clusters of rounded, fleshy polyps, each sitting on its own short skeletal stalk rising from a shared base. When fully inflated the polyps swell into soft, overlapping discs that hide the skeleton completely, giving the colony a texture closer to a soft coral than a stony one. Two species dominate the hobby: B. merletti, with small densely packed polyps, and B. wellsi, with much larger individual polyps. Both are approachable LPS corals.

Merletti, wellsi, and rainbow morphs

Blastos are sorted first by species and then by color pattern:

• Blastomussa merletti — small, tightly packed polyps forming a dense carpet. Faster to spread and the more common of the two in aquaculture.
• Blastomussa wellsi — large fleshy polyps approaching an inch across, spaced further apart. Prized for the dramatic inflation of individual heads.
• Rainbow and multicolor morphs — colonies carrying contrasting rim and center colors across every polyp, which is where the premium sits.
• Red, merlot, and single-tone morphs — deep saturated colors that read strongly against a sand bed and offer good value.

Blastomussa care: light, flow, and placement

Low light and gentle flow are the whole formula, and blastos tell you immediately when you get it wrong by refusing to inflate. Place them on the sand bed or the lower rockwork, shaded from direct beams, in water that moves without pushing. Review your reef lighting before placing a frag anywhere above the bottom third of the tank, and keep alkalinity and salinity steady with dependable water testing equipment. Occasional feeding with fine particulate food supports faster budding but is not required.

A peaceful coral that needs protecting

Blastomussa are one of the few LPS that will not hurt their neighbors, which makes them genuinely useful in a crowded aquascape. The trade-off is that they have almost no defense. A chalice, favia, or torch placed within sweeper range will steadily kill a blasto colony from the edge inward, and the damage is often blamed on water quality before the real cause is found. Site them away from long-reach corals, and if polyps start receding on one side of a colony, look for a neighbor before changing anything else.

Blastos in a low-light reef

Blastomussa belong on the shaded bottom shelf alongside the other calm-water LPS, where their inflated polyps contrast nicely against harder-edged corals. Compare acan corals and favia corals for the same zone, add forgiving companions from our beginner corals selection, or browse the full range of live corals for sale.