Sponges seem to play a greater role in Caribbean reefs than their Asian counterparts and this may not always be a good thing. The reef is beautiful but it is also a battlefield, with everything competing for space and food, including coral and sponges. In a straight fight between a coral and a sponge, the sponge tends to come out as the winner by knockout. With overfishing of Caribbean reefs, sponges have fewer predators and their population has expanded, throwing the ecosystem off balance.