Acan’s as they are affectionately known by those who love them, refer to the brain corals with large coral morph looking polyps of the genus Acanthastrea. Many variations are available within individual species and are collected and coveted by many hobbyists with Acanthastrea lordhowensis being the favourite.  

There are 12 members of the genus, though all species are not as sought after as some of the more colourful types. The Acan’s desired by the aquarium trade are not a common find in a global scale and considered rare in most locations. The highly desirable Acanthastrea lordhowensis is more common on subtropical Eastern Australian reefs. 

Aquarium care

Acan’s are tolerable of a wider range of water parameters and fair well in most aquariums. Avoid excessively high water flow rates to achieve the best puffy display from the coral polyps. Growth rates and health is best when the coral is fed regularly. Important water parameters to maintain healthy Acan’s:

Temp: 22-26C
SG: 1025
Ammonia: 0
Nitrite: 0
Nitrate: <20ppm (low levels can be beneficial)
Phosphate <0.1ppm
PH: 8.0-8.5
Carbonate hardness: 5.5-13 DKH or 2-4.5meq/L.
Calcium: 380-420ppm
Light: Medium through to high end lighting.

Feeding

Small particles <2mm are best, feeding one to three times a week. Simply placing some of left over fish food in a blender usually gets the particles down to the right size, mysid and a mixture frozen prawn, fish, squid and algae’s are all suitable.

Feeding tentacles extend after dark so feed after lights out or a trick we use to feed Acan’s during the day is to add a taste of food to the water first and wait. The coral will react to the flavor in the water and extend its feeding tentacles within a few minutes. After waiting feeding can then be accomplished with the ability of being able to visually check the corals have all received sufficient food.

Propagation

Acan’s rarity and popularity has encouraged aquarists to actively engage in propagation. It can be lucrative to have spare clones of colorful variants to sell or trade.

Propagated Acan’s 

Cutting between individual polyps is the most desirable way to split the parent coral into smaller fragments. This is not so easily achieved, partial polyps will still be viable albeit with some mortalities; don’t discard any smaller fragments generated during the splitting process.  Try them all surprisingly small pieces of partial polyps can still do very well. 

For flatter colonies you can place a sharp blade between the polyps, hitting the blade in a way to force the polyps apart (Brutal but effective all the same!). Alternatively use of a rotary power cutting tool to carefully trim between the polyps can work just as well. Dry cutting generates heat so take it easy and cool the specimen frequently in seawater. The best tool is a lapidary saw that can enable to blade to use seawater as a cutting lubricant. 

Once split individual polyps or smaller colonies will need to be attached to a substrate. Super glue will temporarily hold the coral in place till it encrusts. Expect growth rates of around 1-2cm per annum patience is needed for this coral.

A pictorial on the method we use at Oceanarium to propagate Acan's.
	Using a diamond grinding bit to isolate a single polyp easy in this case because of dead tissue surrounding the polyp.
	The polyp separates away easy rinsed in sea water and is set aside in a tray of sea water.
	A second polyp is cut out and final removal is accomplished with a pair of bone cutters washed and placed with the other polyp.
	When you have everything ready to attach the polyps remove them from the tray of sea water and pat the polyps dry to help the super glue get a good bond.
	One good drop is usually enough.
	Place and allow to dry for a few minutes before replacing into the grow out tank.
	Now wait a year or so !