They form large schools close to the sea floor, and feed on plankton, especially krill, amphipods, small cephalopods, chaetognaths, and ctenophores.
en.wikipedia.org If chaetognaths branched off from the protostomes before they evolved their distinctive protostome embryonic characters, they may have retained deuterostome characters inherited from early bilaterian ancestors.
en.wikipedia.org Most chaetognaths are transparent and are torpedo shaped, but some deep-sea species are orange.
en.wikipedia.org All chaetognaths are carnivorous, preying on other planktonic animals.
en.wikipedia.org These may include fish, chaetognaths, krill, copepods, radiolarians, phytoplankton, nematocysts, ostracods and detritus.
en.wikipedia.org