This article is about chordates and, in detail, about the subphylum vertebrates: Phylum Chordata. This one is about invertebrate chordates and this one is about vertebrate chordates and what distinguished them from invertebrate chordates.
Pelagic tunicates are gelatinous chordates that live in the midwater zone of the ocean. There are a few different kinds including salps, doliolids and pyrosomes. Here are photographs.
Larvaceans are small tadpole like pelagic tunicates that create a large mucus net to catch food.