Tidepool Tim says, “S. ficus has few predators thanks to the unpleasant odor it exudes. Although some gastropods and nudibranchs will dine on it. So will Atlantic bluefin tuna. When these sponges grow on hermit crabs, a symbiotic relationship occurs. The crab will be less tasty for a predator due to the sponge's aroma, and the sponge will stay on the move and avoid nudibranchs."