Septastomates are hermaphrodites and have a very interesting means of mating. On the front end, each septastomate has seven, straight, rigid “straws” arranged in a ring around the male organ. The female organ is located on the back end. Unable to remove the spermatophore from “his” own organ, a partner must reach in with “her” straw-manipulators to pull it out before passing it back to “him” in his own manipulators in order to place it in “her” rear female organ. Sometimes, a third septastomate will pass it along instead and they will take turns inseminating each other. Septastomates live in groups of ten to one hundred where every individual may freely mate with any other and there is no competition. To reduce inbreeding, individuals are often exchanged when groups meet.
The seven straw-manipulators are hollow and open at the end in order to suck up food, but catching food this way is difficult. Instead, they usually grab smaller animals in the manipulators that will escape if they let go. Other septastomates in the group must take these morsels and feed them. Sometimes they grab animals or plants too large to swallow and others must help to break them up into bite-sized pieces. They must cooperate in order to eat or mate. An individual without a group will starve amidst plenty.
There are many families of these strange creatures. Some are straight and fish-like. Others are curled up like snail shells. Unlike false fish, septastomates lack swim bladders so they must constantly flap their ventral fins to keep afloat. Some have “kickstands” for when they rest on the bottom.