A barrel large enough to sit in, and one of the longest-lived animals on the reef: the biggest are estimated at well over a century. Never climb into one.
Individuals reach about 1.8 m high and 1.8 m across. A huge, hard, stony-textured barrel or cone with a deep central cavity at the top. Brownish-red to brownish-grey in shallow water and paler pink-brown deeper. The surface ranges from smooth to deeply ridged and the shape from squat to tall and thin. It is the second most abundant sponge by cover on Caribbean reefs.
The Indo-Pacific giant barrel sponge is visually the same animal and is separated only by ocean. Large soft barrels of other genera are ropier and softer to the eye.
It pumps large volumes of water and filters it, and it hosts dense communities of symbiotic microbes. It lives on hard bottom on the fore-reef and deep slope, usually between about 10 and 40 m and recorded to 120.
Individuals live for more than two thousand years — the largest studied was estimated at about 2,300 — which is why it is called the redwood of the reef. Growth is wildly variable, from more than 400 per cent a year to two per cent. It suffers from sponge orange band disease, an advancing orange band of dying tissue whose cause and transmission are still unknown.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
