The bacteria benefit by having a place to live, and source of food.These light-producing bacteria are drawn into an organ on the bottom of the squid. There is a mutualism symbiosis relationship between some squid and the bacteria “vibrio fischeri”.Symbiotic Interactions with Other Species Squids can expel ink to blind predators while making an escape.Although they don’t have vertebrae (backbones), they do have one big flat bone inside for defense, like an internal shell.Squids often camouflage with their surroundings so they can hide form predators, such as the Moray Eel and the Reef Shark.Squids have a sharp beak made out a hard material called chitin that they use to kill and tear apart fish.They use their long tentacles for catching and pulling in prey.Squids are carnivores that eat smaller fish, such as the Clownfish and the Parrot Fish.The Great Barrier reef is home to about 4000 different types of mollusks, about 300 of which are squids.They live in oceans all over the world, especially around coral reefs.Most species of squids are no more than 60 centimeters long, but they range from tiny carribean reef squids (20 centimeters) to giant squids and colossal squids which can be up to 13 or 14 meters long!.They usually only live for one year, and they die after they spawn (reproduce).They have eight arms and two long tentacles with suckers.Squids are mollusks, similar to octopuses, but with a few major differences.