Thysanostoma? Jellyfish off Ataúro Island

Sighted on coral reef ~100m off the south coast of Ataúto Island, Timor-Leste. Approx 1.5 metres length. Seen at depth ~2m before floating off into deep open waters.
Long, rope-like tentacles, pinkish-white bell, a small black fish was seen seeming living amongst its tentacles.