Scientific Name: Hydnophora SP
Common Name:, Horn Coral, Hydno Coral, Velvet Horn Coral
Type of Coral: SPS  (Small Polyp Stony Coral)
Lighting: High
Flow: High
Care Level: Moderate to Difficult
Temperament: Semi-aggressive to aggressive

Appearance

This is a branching SPS coral, as with many other commonly found SPS corals. It can range in color from a brown or cream color to a bright neon green color.  The surface of the coral will be covered in very short than thick polyps almost giving it an appearance of being covered in “fur”.

Water Conditions

The below link highlights typical water conditions horn corals, as with most SPS, will require.  As this is a moderately difficult to very difficult coral to keep, you should ensure your dKH, Cal and Mag levels are maintained at all times with nitrate and phosphate levels almost undetectable by very good quality test kits. This coral will not tolerate changes in water chemistry very well at all.  As this coral also has a calcified skeleton, it will consume calcium from your water.  In set-ups with a good amount of SPS corals, it is not uncommon to have to dose dKH and Cal in order to keep the water parameters in line.

https://www.reefaquarium.com/2013/the-basics-of-marine-aquarium-water-parameters/

General Information

Horn corals as with all other SPS corals, should only be added to mature aquariums. Provided all their requirements are met, they can grow very large to about 12 inches.  Horn corals typically do best when placed on top of rocks, closer to the aquarium lighting and in areas of higher flow.  When provided with the correct conditions, they will grow very fast in an aquarium.

The horn coral can be a somewhat aggressive SPS coral.  It will sting other corals close by. The horn coral would require a distance of around 3 to 4 inches from other corals

Generally speaking, SPS corals can also benefit from the occasional feeding micro-plankton designed for filter feeders

Fragging

As with all SPS, they can be fragged with very good success assuming the environmental conditions in the aquarium are suited to SPS corals