[Subsea]

First that I have heard about Halymenia going sexual. It is a slow growing rigid macro algae. With respect to macro going sexual in a tank, it happens when fast growing macroalgae consume available nutrients and starve. At this point, macro disperses spores into bulk water.

I have many lagoon biotheme with red and green macros contrasted with red and green inverts. Favorite red macros are Dragons Tongue, Red Grapes and Gracilaria Hayi. Favorite green macro is Grape Caulerpa and Caulerpa Prolifera. Prolifera will look like oar sea grass in your substrate. Keep it off your desirable live rock because holdfast are hard to remove and quickly come back. Not so with Grape Caulerpa. It’s holdfast are easily removed.