The bright white skeleton is completely intact, with no living tissue. Touch the skeleton and it breaks up like granulated sugar. In Montastraea annularis, RWD can be seen on the tops of the coral heads and on Colpophyllia natans , it occurs around the rim and on a few areas throughout the coral structure. During the beginning stages of RWD, measurements show the spread to be one to two inches per day, then slowing after a month. There is no distinct boundary between the eroded skeleton and live tissue.
Algae quickly overgrow the skeleton.
Also, RWD and YPD are seen in areas where algal species, unfavorable to corals, occur. The presence of these algal species have been linked to excess nutrients from leaky septic tanks, poor sewage systems and high runoff from fertilizers. This disease was also seen in close proximity to Rapid Wasting Disease in the Antillies region. Both affect the major reef builder Montastraea annularis. Yellow Pox is slow acting and can be seen with round yellow rings on the sides of the coral.