Acropora hoeksemai is a gorgeous blue staghorn Acro which been a classic Indonesian coral, produced in the thousands through mariculture. So you would think that this coral is probably available all over the world right now, through frag sellers, but its abundance in the wild is not reciprocated in the reef aquarium hobby.
We’ve been growing this species for almost two decades, and it has always been a temperamental species – it’s very sensitive to bleaching, and even though it comes from warm water area, it’s the first one to go when the temperature goes up, out of normal range.
Following a conversation about it, with a good friend in the US, struggling to get it to grow properly, we thought that it was worth a post. It’s important that peoples are successful with this coral, as it can’t get imported from Indonesia at the moment. But this deep purple coloration with bright green corallite opening is quite a sight to remember.
This coral can be found in very turbid, protected, calm bay. Its skeleton is quite porous, and it grows quite fast in shallow silty water often around 5-10 m (15-30 feet). Even if it comes from turbid water, it still like quite a lot of light, but giving it more flow, will force it to thicken its skeleton and the growth will be slower.
The green on the inside of corallites tends also to be brighter in turbid waters. Where we would always get the fastest growth, was in the ‘soup’ of these mangroves, oyster-filled bays, so feeding is important. The brilliant topaz color varies from blue to purple blue depending on the conditions and spectrum of the lighting used.
It took us actually quite many years and the cross referencing with Garden Wallace book ‘Staghorn Corals of the World’ to identify it with certainty. And we only ever met this colour morph only in the lesser Sunda island groups of Easter Indonesia- Radial corallites are homogenous, evenly sized and distributed, not touching on the branches, tubular with a nariform (nose-shaped) outline but dimidiate opening.
When culturing Acropora hoeksemai, we used to take them from a calm bay up north, and cook them for a month in the south with clear and cool oceanic water where they would get very deep purple with bright green polyps, but would almost stop to grow, and if left there, would die after 2 to 3 months.
The unapologetically blue staghorn coral Acropora hoeksemai is really a classic beauty, and we hope that this information will help you to keep this strain growing in the hobby all around the world.