Why does my Black Widow Blastomussa shrink during the day but puff up at night?

B. wellsi often expands after lights dim to feed on suspended plankton. Daytime “shrinking” can be normal, but if tissue hugs the skeleton for days, check for excess light or vermetid snail irritation. Lower PAR gradually (mesh or screen acclimation), reduce direct flow, and inspect for mucus nets. Stable alk 8–9 dKH and nitrates 5–15 ppm support recovery.

My coral’s red turns dull and the center darkens—lighting or nutrients?

Both. Too much white spectrum or sudden PAR increases can wash reds; very low nutrients mute pigmentation. Aim for moderate PAR (60–120), stronger blue weighting, and balanced nutrients (NO3 5–15 ppm, PO4 0.03–0.1). Trace stability helps: regular water changes, avoid aggressive GFO swings. Improve color slowly over 2–4 weeks to avoid stress.

The tissue is receding from the base upward, but parameters look fine—what else should I check?

Look for mechanical irritation and nocturnal stressors: vermetid snail tubes, bristle stars wedging polyps, or laminar flow hitting the collar. Redirect flow to be broad and gentle, break off vermetids, and place the colony on a smooth, sandbed “island” or a flat rock. Run fresh carbon to reduce chemical aggression from nearby LPS like favias or euphyllias.

Can feeding too often cause problems with this coral?

Yes. Overfeeding can foul tissue and invite bacterial issues (including brown jelly). Target feed small portions of fine meaty foods 1–2 times weekly after tentacles extend; ensure enough flow after feeding to clear leftovers. Skip feeding if polyps look stressed or are mid-recovery. Prioritize overall stability; consistent nutrients and gentle flow often improve plumpness more than heavy feeding.

TSA Black Widow Blastomussa Coral

Blastomussa

Overview

Black Widow Blastomussa Coral displays fleshy, deep red to maroon polyps with darker centers and visible radial striping. Blastomussa wellsi is a large‑polyp stony coral that forms clustered heads and prefers moderate light with low to moderate, indirect flow. It is photosynthetic with symbiotic algae but accepts small meaty foods, which can improve growth and color. Place on a stable sandbed or lower rockwork, acclimate to light changes, and give space from more aggressive corals.

Quick Facts

Care Moderate

Lighting Low–Moderate

Flow Low–Moderate

Placement Low–Mid

Temperament Semi-aggressive (2–3 inches spacing)

Recommended Parameters

Temp 76–80°F

pH 8.1–8.4

Salinity 1.025–1.026

Calcium 400–450 ppm

AlkAlkalinity 8–9 dKH

Magnesium 1280–1350 ppm

Feeding photosynthetic, mysis shrimp, enriched brine shrimp, finely chopped marine meaty foods, zooplankton, microplankton, copepods, rotifers, powdered coral foods (e.g., Reef-Roids)

Care & Placement

Black Widow Blastomussa Coral (Blastomussa wellsi) prefers low to moderate light (PAR ~50–120) and gentle, indirect flow that keeps tissue moving slightly and prevents detritus from settling in the heads. Start in lower areas and slowly increase light over 2–3 weeks to avoid bleaching; shaded lower rockwork or the sandbed on a small rubble piece works well. Target feed 2–3 times weekly with small meaty foods (mysis, enriched brine, finely chopped seafood, reef-safe microfoods) when feeder tentacles extend after lights dim. Keep temperature 75–79°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; maintain nitrate 5–15 ppm and phosphate 0.03–0.1 ppm for color and polyp inflation. Test weekly, use a refractometer for salinity, and avoid sudden changes.Place with at least 2–3 inches of space from stinging LPS (e.g., euphyllia, favia). Blastomussa is generally peaceful with short sweepers but can be damaged by aggressive neighbors and sand abrasion; gently baste off debris. Drip acclimate, then dip to reduce pests; use light acclimation screens if moving up. Signs of stress include retracted polyps, tissue recession, or paling. If recession starts, reduce flow, check alkalinity stability, and consider an iodine or antibacterial dip; remove dying heads to stop spread. Guard fed pieces from food-thieving shrimp, and keep fish that nip fleshy corals away. Stability and moderate, consistent care yield steady growth and vivid coloration.

FAQ

Frequently Asked Questions

About the TSA Black Widow Blastomussa Coral

Why does my Black Widow Blastomussa shrink during the day but puff up at night?

B. wellsi often expands after lights dim to feed on suspended plankton. Daytime “shrinking” can be normal, but if tissue hugs the skeleton for days, check for excess light or vermetid snail irritation. Lower PAR gradually (mesh or screen acclimation), reduce direct flow, and inspect for mucus nets. Stable alk 8–9 dKH and nitrates 5–15 ppm support recovery.
My coral’s red turns dull and the center darkens—lighting or nutrients?

Both. Too much white spectrum or sudden PAR increases can wash reds; very low nutrients mute pigmentation. Aim for moderate PAR (60–120), stronger blue weighting, and balanced nutrients (NO3 5–15 ppm, PO4 0.03–0.1). Trace stability helps: regular water changes, avoid aggressive GFO swings. Improve color slowly over 2–4 weeks to avoid stress.
The tissue is receding from the base upward, but parameters look fine—what else should I check?

Look for mechanical irritation and nocturnal stressors: vermetid snail tubes, bristle stars wedging polyps, or laminar flow hitting the collar. Redirect flow to be broad and gentle, break off vermetids, and place the colony on a smooth, sandbed “island” or a flat rock. Run fresh carbon to reduce chemical aggression from nearby LPS like favias or euphyllias.
Can feeding too often cause problems with this coral?

Yes. Overfeeding can foul tissue and invite bacterial issues (including brown jelly). Target feed small portions of fine meaty foods 1–2 times weekly after tentacles extend; ensure enough flow after feeding to clear leftovers. Skip feeding if polyps look stressed or are mid-recovery. Prioritize overall stability; consistent nutrients and gentle flow often improve plumpness more than heavy feeding.