Euphyllia ancora

Medium flow and medium light. Under too much of either the tentacles stay short and the colony stops extending past its skeleton, which is the first thing you will notice and the easiest to fix.

Give it room. Euphyllia put out sweeper tentacles at night that reach far past the visible flesh — fifteen centimetres is ordinary — and whatever is inside that radius loses. A hand’s width of bare rock is not wasted space.