なぜ私の Sarcophyton leather coral は開かず、藻が生えているのでしょう

Question

Sarcophyton leather coral のことで助けてください

こんにちは、みなさん！Sarcophyton leather coral についてアドバイスをいただきたくて投稿しました。

もう1か月ほど開かず、ポリプも伸びていません。サンゴ自体は触るとまだ柔らかく、水流に合わせて自然に揺れていますが、表面には藻のような緑の斑点が出てきています。

上の方に膜のようなものができるのに気づきました。一度やさしく取り除いたのですが、またできてきているようです。

近くにある他のサンゴはどれも元気なのに、この Sarcophyton だけまだ開きません。

同じような経験をした方はいますか？何が原因として考えられるでしょうか、回復のために何をしたらいいでしょうか？

どんなアドバイスでも本当にありがたいです。ありがとうございます！

Pierre · Answer

Trapped Shedding Mucus (Wax Sheen & Algae Build-Up):
 The Mechanism: Leather corals regularly contract and produce a waxy, glossy layer of mucus to slough off built-up waste, epiphytic algae, and detritus.  
 The Issue: If water movement across the crown is too weak, the coral cannot cast this layer off. It remains glued to the tissue, suffocating the surface and allowing opportunistic microalgae (the visible green patches) to take hold. While locked in a shed cycle, the coral cannot extend polyps to feed or photosynthesize efficiently, halting growth.  
 Allelopathy and Sweeper Contact:
 The proximity of the neighboring Euphyllia tentacles triggers defensive retraction. Leather corals will refuse to expand when irritated by nematocysts or encroaching sweeper tentacles.  
 Nutrient / Iodine Demand:
 Soft corals like Sarcophyton consume trace elements (particularly dissolved organics and iodine) during shedding and tissue expansion. Zero-nutrient (ultra-low nutrient) systems often lead to extended sulking.
Immediate Action Steps
1. Baste the Surface: Use a turkey baster to gently puff water directly across the crown to help lift the peeling film and green algae layer without tearing live tissue.
2. Increase Flow Immediately: Adjust the nearest powerhead or relocate the coral into an area with stronger, multi-directional flow so the surface tissue visibly ripples.
3. Ensure 6" Clearance: Move the coral away from the Euphyllia to eliminate stinging and chemical stress.
4. Inspect Water Chemistry: Confirm specific gravity is stable at 1.025–1.026 and nitrates sit comfortably between 5–15 ppm to support soft coral tissue expansion.