Fastest growth rate for a marine invertebrate

The giant tube worm (Riftia pachyptila), famed for its huge red tentacles and only being discovered by science as recently as 1977 (when huge colonies of these spectacular creatures were found around hot-water vents on the Pacific Ocean floor), has the most rapid growth rate measured for any type of marine invertebrate. In under two years, these worms have been recorded colonising a new site, growing to sexual maturity, and increasing in length to 1.5 metres (4 feet 10.8 inches).