Why does Death Grimace Tenuis change color under different lights, and how can I lock in the vivid hues?

Acropora tenuis pigments respond strongly to spectrum, PAR, and nutrients. Blues/violets (420–460 nm) with PAR ~300–400 tend to deepen blues and purples; moderate whites keep contrast. Keep nitrate 2–10 ppm and phosphate 0.02–0.08 to avoid pastels or browning. Stable alkalinity 8–9 dKH and steady salinity are key. Trace balance helps: potassium for pinks, iodine/iron for blues/greens—dose only after ICP confirmation.

My tenuis encrusts, then the base slowly recedes while tips look fine. What’s causing this “shadow STN”?

It’s often micro-shadowing plus detritus accumulation. As branches thicken, the base gets less light and flow, encouraging bacterial irritation. Raise the frag to reduce shading, add cross-flow from multiple directions, and ensure 250+ PAR reaches the base. Siphon detritus weekly. Verify low but present nutrients; starvation worsens recession. Consider a short course of increased turbulence rather than more intensity.

Are there pests this species is especially vulnerable to, and how do I catch them early?

Acropora-eating flatworms and red bugs favor tenuis. Look for crescent bite marks, sand-like eggs on the underside, and reduced daytime polyp extension. Inspect with a white flashlight and turkey baster—AEFW dislodge as oval, translucent flakes. Quarantine new pieces, perform sequential dips a week apart to target hatch cycles, and use a magnifier weekly. Polyp extension returning after lights out is a good early recovery sign.

Can I place this coral near soft corals or torches without issues?

Keep generous spacing. Euphyllia sweeper tentacles can burn tenuis tissue quickly. Soft corals, especially leathers, release terpenes that suppress polyp extension and growth. Run fresh activated carbon, maintain strong export, and aim alternating flow so allelochemicals don’t stagnate around the colony. If color dulls after adding softies, swap carbon more frequently and increase water changes until response improves.

TSA Death Grimace Tenuis Acropora Coral

Acropora

Overview

Death Grimace Tenuis Acropora Coral shows compact corymbose branches with fine axial tips and contrasting polyp coloration. Acropora tenuis is a small-polyp stony branching coral that prefers strong light and moderate to high, alternating flow. It is primarily photosynthetic via symbiotic algae but benefits from occasional small-particle foods, which can support growth and color. Place high on stable rockwork with ample space from aggressive neighbors, and keep alkalinity and other parameters stable to prevent stress.

Quick Facts

Care Difficult

Lighting High

Flow High

Placement High

Temperament Semi-aggressive (3–6 inches spacing)

Recommended Parameters

Temp 76–80°F

pH 8.1–8.4

Salinity 1.025–1.026

Calcium 400–450 ppm

AlkAlkalinity 7.5–9 dKH

Magnesium 1280–1350 ppm

Feeding photosynthetic, microplankton, rotifers, copepod nauplii, coral-specific powdered foods, amino acids

Care & Placement

Death Grimace Tenuis Acropora Coral (Acropora tenuis) thrives in very stable, nutrient-balanced reef systems. Provide high light (PAR 250–350, blue-heavy spectrum) and strong, random, turbulent flow to keep polyps active and prevent detritus settling on branches. Place it high to upper-mid in the rockwork, with 2–4 inches of space from neighbors; avoid contact with aggressive LPS sweepers and allow room for fast encrusting growth. Target feed fine particulate foods (0.5–200 microns) or broadcast feed at night 1–3 times weekly to support polyp extension and coloration, but keep nutrients controlled: nitrate 2–10 ppm, phosphate 0.02–0.08 ppm. Maintain temperature 75–79°F (24–26°C), salinity 1.025–1.026 (35 ppt), pH 8.1–8.4, alkalinity 8.0–9.5 dKH (very stable), calcium 420–460 ppm, magnesium 1280–1380 ppm. Test alkalinity and nutrients 2–3 times weekly, calcium/magnesium weekly, and consider monthly ICP for trace issues.Acclimate by dipping, inspecting for pests (AEFW, red bugs), and quarantining 4–6 weeks when possible. Light-acclimate by starting 30–50% dimmer or lower placement, then ramp over 1–2 weeks. Avoid direct pump jets; aim for crossflow that ruffles polyps. Signs of stress: paling/bleaching (too much light or low nutrients), tissue recession (instability, pests, or low flow), burnt tips (alk spikes). Correct by stabilizing parameters, slightly reducing light, increasing random flow, and addressing pests; frag healthy branches if recession advances. Mount on a stable, clean plug or rock shelf with good airflow and keep export strong (skimming, refugium, regular filter maintenance). Regularly baste branches to keep them clean.

FAQ

Frequently Asked Questions

About the TSA Death Grimace Tenuis Acropora Coral

Why does Death Grimace Tenuis change color under different lights, and how can I lock in the vivid hues?

Acropora tenuis pigments respond strongly to spectrum, PAR, and nutrients. Blues/violets (420–460 nm) with PAR ~300–400 tend to deepen blues and purples; moderate whites keep contrast. Keep nitrate 2–10 ppm and phosphate 0.02–0.08 to avoid pastels or browning. Stable alkalinity 8–9 dKH and steady salinity are key. Trace balance helps: potassium for pinks, iodine/iron for blues/greens—dose only after ICP confirmation.
My tenuis encrusts, then the base slowly recedes while tips look fine. What’s causing this “shadow STN”?

It’s often micro-shadowing plus detritus accumulation. As branches thicken, the base gets less light and flow, encouraging bacterial irritation. Raise the frag to reduce shading, add cross-flow from multiple directions, and ensure 250+ PAR reaches the base. Siphon detritus weekly. Verify low but present nutrients; starvation worsens recession. Consider a short course of increased turbulence rather than more intensity.
Are there pests this species is especially vulnerable to, and how do I catch them early?

Acropora-eating flatworms and red bugs favor tenuis. Look for crescent bite marks, sand-like eggs on the underside, and reduced daytime polyp extension. Inspect with a white flashlight and turkey baster—AEFW dislodge as oval, translucent flakes. Quarantine new pieces, perform sequential dips a week apart to target hatch cycles, and use a magnifier weekly. Polyp extension returning after lights out is a good early recovery sign.
Can I place this coral near soft corals or torches without issues?

Keep generous spacing. Euphyllia sweeper tentacles can burn tenuis tissue quickly. Soft corals, especially leathers, release terpenes that suppress polyp extension and growth. Run fresh activated carbon, maintain strong export, and aim alternating flow so allelochemicals don’t stagnate around the colony. If color dulls after adding softies, swap carbon more frequently and increase water changes until response improves.