Traits

Wings are replaced with jellyfish like tentacles

Webbing between hands

Sea plant life such as seaweed grow on them

Electrified nematocysts, similar to jellyfish and their electrified tentacles 

Bones that are all coral

Blood that is completely made out of ink, allowing for a quick escape under water as it acts like a smokescreen. Only works underwater though, out of water its just inky

A jaw with 3 times the PSI bite force of a normal opexo

Lungs that are twice the size of an average opexo's allowing them to hold their breath for a long time underwater, though they still need to come up for more oxygen as it does not allow for breathing under water

A skirt of tentacles that drape around the opexo's waist, they are fully functional and have suckers underneath them, some having a membrane between them