Why does my Black Widow Blastomussa inflate and deflate dramatically through the day?

B. wellsi regulates water content to optimize gas exchange and feeding. Large mid-day deflation often points to excess PAR or direct flow. Aim for low–moderate light (60–120 PAR), diffused flow, and a blue-heavy spectrum. If deflation persists, check alkalinity stability and look for irritants like vermetid snail webs or sand grains trapped under tissue.

How can I keep the deep black and red coloration from washing out?

Keep PAR modest and avoid heavy white channels; prioritize 420–450 nm blues. Maintain steady nutrients (NO3 5–15 ppm, PO4 0.03–0.1 ppm) and feed small meaty foods at dusk 2–3 times weekly. Rapid increases in light or alkalinity swings commonly mute reds. Ironically, ultra-low nutrients pale this morph; don’t strip the tank too clean.

What’s the safest way to frag a Black Widow colony with tightly packed corallites?

Use a diamond band saw to cut the skeleton between corallite walls, not through fleshy tissue. Chill or briefly air-expose to slightly deflate first, then rinse, cut, and give an iodine dip. Mount on a smooth plug to avoid abrasion. Moderate flow and stable alk help heal; expect 2–4 weeks for full polyp extension.

My Blastomussa recedes from the base upward—what rare causes should I check?

Beyond basic parameters, inspect for vermetid snails under the rim, bristleworms irritating night-time feeders, and detritus trapping at the base. Brown jelly can start in shaded crevices—siphon immediately and dip. Chronic recession often traces to pulsing alkalinity or micro-shadows from rock edges; lift onto a smooth, slightly raised platform to keep tissue off grit.

Black Widow Blastomussa Coral

Overview

Black Widow Blastomussa Coral displays large, fleshy polyps with dark red to maroon discs and contrasting black or green centers. Blastomussa wellsi is a large-polyp stony coral forming low, dome-shaped clusters; it prefers low to moderate lighting and gentle to moderate water flow. It is photosynthetic via symbiotic algae but benefits from occasional small meaty feedings, which can support faster growth and richer color. Place in a stable, low-flow area with space from neighbors, as it can sting nearby corals, and acclimate slowly to brighter light.

Quick Facts

Care Moderate

Lighting Low–Moderate

Flow Low–Moderate

Placement Low–Mid

Temperament Semi-aggressive (3–4 inches spacing)

Recommended Parameters

Temp 76–80°F

pH 8.1–8.4

Salinity 1.025–1.026

Calcium 400–450 ppm

AlkAlkalinity 8–10 dKH

Magnesium 1250–1350 ppm

Feeding photosynthetic (primary), mysis shrimp, enriched brine shrimp, finely chopped shrimp or clam, cyclops/copepods, rotifers, zooplankton, LPS pellets, coral-specific powdered foods

Care & Placement

Black Widow Blastomussa Coral (Blastomussa wellsi) prefers low to moderate light (50–100 PAR) and gentle, indirect flow that keeps its fleshy polyps moving lightly without folding. Place it low to mid in the tank on a stable rock ledge or protected sandbed, avoiding direct blast from pumps and intense light spill. Leave 2–3 inches of space from neighbors; it’s generally peaceful with short sweepers but can be irritated by aggressive LPS. Feed 2–3 times weekly with small meaty foods (mysis, chopped brine, reef pellets, or fine coral foods) 15–30 minutes after lights dim to support growth and color. Maintain stable parameters: temperature 75–78°F (24–26°C), salinity 1.025–1.026, pH 8.1–8.4, alkalinity 8.0–9.5 dKH, calcium 400–450 ppm, magnesium 1250–1350 ppm, nitrate 2–15 ppm, phosphate 0.03–0.08 ppm. Test weekly and avoid rapid swings, especially in alkalinity and salinity.Acclimate with a 30–60 minute drip and reduce light for the first week using shade or screen. Dip on arrival to rule out pests; inspect for vermetid snails and algae at the base. Use a turkey baster to blow off detritus; detritus buildup can cause tissue recession. Signs of stress include gaping mouths, tight retraction, paling, or brown jelly—improve flow slightly, stabilize parameters, reduce light, and consider an iodine dip if tissue is sloughing. If bleaching occurs, lower PAR and increase feeding until color returns. Keep nutrients non-zero; ultra-low nutrients can stall growth and fade color.

FAQ

Frequently Asked Questions

About the Black Widow Blastomussa Coral

Why does my Black Widow Blastomussa inflate and deflate dramatically through the day?

B. wellsi regulates water content to optimize gas exchange and feeding. Large mid-day deflation often points to excess PAR or direct flow. Aim for low–moderate light (60–120 PAR), diffused flow, and a blue-heavy spectrum. If deflation persists, check alkalinity stability and look for irritants like vermetid snail webs or sand grains trapped under tissue.
How can I keep the deep black and red coloration from washing out?

Keep PAR modest and avoid heavy white channels; prioritize 420–450 nm blues. Maintain steady nutrients (NO3 5–15 ppm, PO4 0.03–0.1 ppm) and feed small meaty foods at dusk 2–3 times weekly. Rapid increases in light or alkalinity swings commonly mute reds. Ironically, ultra-low nutrients pale this morph; don’t strip the tank too clean.
What’s the safest way to frag a Black Widow colony with tightly packed corallites?

Use a diamond band saw to cut the skeleton between corallite walls, not through fleshy tissue. Chill or briefly air-expose to slightly deflate first, then rinse, cut, and give an iodine dip. Mount on a smooth plug to avoid abrasion. Moderate flow and stable alk help heal; expect 2–4 weeks for full polyp extension.
My Blastomussa recedes from the base upward—what rare causes should I check?

Beyond basic parameters, inspect for vermetid snails under the rim, bristleworms irritating night-time feeders, and detritus trapping at the base. Brown jelly can start in shaded crevices—siphon immediately and dip. Chronic recession often traces to pulsing alkalinity or micro-shadows from rock edges; lift onto a smooth, slightly raised platform to keep tissue off grit.