can help what with this eel behavior?

[Caveden]

View attachment 1511801
excuse me, can ask what is this behavior means?
are eel known can do this? or signs of stress or something?

View attachment 1511807 standard state
Macrognathus maculatus Zig-zag eel

I would fear more about the gar or bichirs eating it eventually

 

[Umbra]

It sounds strange but some fish are just weird - I have a Gymnallabes typus that refuses to hide and instead sits at one of the front corners of the tank completely out in the open. It literally does not move until I put food in the tank at which point it it gorges itself, returns to its corner and just sits there doing nothing again.

Tank has a ton of hides and no other bottom dwellers to compete with it.