Ladysmith Marina

Noted immediately in front of our boat, in its slip in the marina. Images attached were found on web, but this is what we saw! What is the name of this particular species? Very beautiful!!! Approx 1 to 1.5 cm in diameter, two flagella one on either side, that are approximately 1 cm long when at rest, and up to 10cm long when extended to set the jellyfish in motion. They set themselves into a spin and produce fantastic multi-coloured light show. Do they do this for sexual attraction? No predators were apparent, and nothing to be aggressive toward.