Acanthella cavernosa(TOPSENT, 1892)
Author: Bob Goemans
Range: Indo-Pacific Ocean
Natural Environment: This sponge is usually found encrusting various substrates near or in caves where water currents are fairly swift. It is a filter feeder, feeding upon plankton, bacteria, and suspended detritus. Depending upon its area of origin, various color varieties a
Captive Care: This is a non-photosynthetic, filter-feeding animal, and it requires shaded areas receiving excellent water movement. It requires at least one daily feeding of live and/or preserved commercial phytoplankton and zooplankton products, or that of animal and plant powders that produce suspended products in the water column. Even though it prefers somewhat nutrient-rich surroundings, it will not tolerate algal growth.
Generally, almost all sponges are difficult to maintain long term, and this beautiful species is no exception. It should be kept in systems designed to meet its needs, not simply as a colorful addition to a new reef tank or even that of a thriving reef system if its nutritional needs cannot be met. Their long-term survival rate in closed systems (i.e., aquariums) is highly questionable, and if its needs cannot be fulfilled, its better left in the wild.
Notes: Sponges are the simplest of multicellular creatures. There are over 15,000 species. Most are found in marine waters, and they vary in size, shape, and color. They posses no nervous, digestive, nor excretory systems, and most feed by filtering suspended bacteria and fine detritus. Strong water movement is vital to almost all, not only for carrying food to these sessile creatures but also to carry waste/unused matter away. In fact, a sponge the size of a baseball can filter 50 gallons of water per hour! Most do best only in low light areas and where currents are quite swift.
Each sponge has both female and male reproduction capabilities. Cutting a piece from the healthy tissue and simply relocating it to another suitable area can form a new colony. Bear in mind, the new specimen should not be exposed to air during this procedure, as that may kill it. When purchasing new specimens, they should be bagged under water, never lifted out of the water. Nor should any air or oxygen be added to the bag, as it may become trapped in the animal's tissue while be transported and lead to its early demise. They are not too sensitive to temperature changes, yet sudden changes in salinity may have drastic effects.
New colorful specimens should not contain any gray or white tissue, which is generally a sign of dying or dead tissue. However, it is possible to cut that section out—again, of course, under water. Sponges should be placed in shaded areas where water movement is very good and detritus or algae do not accumulate on their surface.
Water Requirements: Calcium 380 to 430 ppm, alkalinity 3.5 meq/l, pH 8.1 to 8.2, specific gravity 1.024 to 1.026, and a temperature range of 74° to 83°F (23° to 28°C).