This one is also unfortunately a bit light on description, as there's not too much to work off.

Do Common Gilltails have any resistance to these?
How do they detect gills and breathing apparatuses? Oxygen? Carbon dioxide? How do they adapt to various gill-or-breathing-apparatus structures? Do they have color variations for the twilight zone? Do they occur in brackish waters? Are they more or less common in low-oxygen waters or polar waters?

Don't forget that Scuttlers are plents

Oh right, mixed them up with scuttlecrabs.

"among other" is a typo. You forgot to add an 'S'.

Fixed