one of the distinct individuals forming a colonial animal such as a bryozoan or hydrozoan
no
planula
hydrozoan, coral, anemone, jellyfish
yes
(Portuguese) man of war is Physalia physalis, a siphonophore hydrozoan. Or, a jellyfish.
Yes; some hydrozoan jellyfishes can reproduce asexually by gemmation (with buds) and by direct scission.
Some hydrozoan, aka hydromedusae, are found in fresh water.
Portuguese Man o war
yes. A Portuguese man-of-war is a large hydrozoan, having an aerial float and long stinging tentacles.
Gonionemus refers to a genus of hydrozoan; it is a jellyfish that inhabits the waters off of northern Japan and Russia as well as the waters off of the Aleutian Islands and northern California.
The common names of many animals preceded their classification into modern taxonomy. Jellyfish-like organisms may still be called jellyfish (Portuguese man-o'-war, a hydrozoan). Some jellyfish have names that differentiate them from other jellyfish (sea nettles).