As far as my knowledge cutoff date in September 2021, there were no well-documented folk beliefs or legends specifically associated with coelacanths. These fish were largely unknown to the wider world until their rediscovery in the 20th century. However, in some regions where coelacanths are found, there might be local stories or folklore related to unusual deep-sea creatures, but specific tales about coelacanths are not widely known.
It's worth noting that the rediscovery of coelacanths in the 20th century did lead to their iconic status in the field of biology and the popular imagination, as they are often referred to as "living fossils" due to their ancient lineage and the belief that they went extinct with the dinosaurs. This fact, along with their unique appearance, has contributed to their cultural significance. If there have been any developments or folk beliefs related to coelacanths after my last knowledge update, I would not have information about them.