WYSIWYG Rainbow Blastomussa Colony

You are buying the exact coral in the photo — a Rainbow Blastomussa colony photographed under blue spectrum reef lighting. The polyps inflate into overlapping fleshy discs covered in fine raised bubbles, each one running a deep magenta-rose across the body with hot pink septal lines radiating out from a dark center. Where the polyps meet, the tissue breaks into bands of acid yellow and chartreuse, and each mouth is ringed in the same yellow — the combination is what earns this one the rainbow label rather than a single-color designation. Polyps are fully inflated with no recession between heads. conditioned in our Key West systems, Florida under FL Aquaculture Certificate #AQ0254072.

About Blastomussa (Blastomussa sp.)

Blastomussa are among the most underrated LPS in the hobby: they build slowly into dense mats of individually stalked polyps, they tolerate lower light than almost anything else with this much color, and a settled colony inflates far larger than its skeleton suggests. Rainbow morphs — where a single polyp carries three or more distinct pigments rather than a body color and a mouth color — are the ones that hold value, and they are notoriously hard to photograph accurately because the yellows only fire under blue light. This colony was grown out in Key West on stable parameters, so the polyps are conditioned to captive lighting and open fully.

Care Guide

One of the easiest LPS you can own, and a strong choice for a lower-light corner of the tank that needs color.

• Lighting: Low to medium — PAR 50–150. Blastos color best under modest light; strong lighting causes the polyps to stay closed.
• Flow: Low to moderate — gentle, indirect. Too much flow and the polyps will not inflate.
• Placement: Sandbed or lower rockwork, tucked into a shaded spot if your lighting runs hot.
• Feeding: High — meaty foods. Mysis or small LPS pellets a few times a week will push new polyp growth.
• Aggression: Semi — no long sweepers, but give it room to expand as the colony spreads.
• Water Parameters: Temp 76–78°F, salinity 1.025–1.026, Alk 8–9 dKH, Ca 420–440, Mg 1300–1400. Stability matters more than exact numbers.

Ships UPS Next Day Air every Tuesday and Wednesday from Key West, Florida. Packed with insulated box and heat or cold pack appropriate for current conditions. Specimen is carefully secured to prevent movement during transit.

Placement: Sandbed or lower rockwork — a shaded spot if your lighting runs bright, with room to spread.

Not sure how to keep it? See the large polyp stony corals in our Coral Field Guide — ID notes, PAR, flow, placement and aggression, next to the corals people mistake them for.

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What to expect when it arrives

Acans arrive deflated with the skeleton visible between polyps, which looks worse than it is. Float the sealed bag 15 minutes, drip acclimate 30 to 45 minutes, and place the frag low in the tank with gentle flow. Most acans begin inflating within 24 hours and are fully puffed within two to three days.

Placement, and the light mistake

Acans burn under SPS lighting. Start low — sand bed or the bottom third of the rockwork — and leave it there. A deflated acan sitting under strong light is not going to adapt; it is going to recede. Flow should be gentle and indirect enough that the fleshy polyps are not visibly pushed around.

Feeding, which is the whole point

This is where acans reward you. Target feed with a small meaty food two or three times a week, pumps off for ten minutes, placing food directly on the polyps. A fed acan produces new heads at the frag edge within weeks. An unfed one can sit unchanged for a year and many keepers conclude the coral is slow when it is simply hungry.

Growth and fragging

A three-head frag that is placed correctly and fed regularly commonly becomes eight to ten heads within a year. New heads emerge at the margin and mature over a few months. Frag by cutting between heads with a band saw or bone cutters once the colony has spread past its plug.

Compatibility

Acans have short sweepers and lose most exchanges. Keep them clear of Euphyllia and chalices. They are also a favorite target for some angels and butterflies, and a colony that stays deflated in otherwise good conditions is usually being picked at after lights out.