I guess nobody else was stupid like I was one night and forgot to switch out my dwarf pugils for meatballs and managed to catch maybe 5 cherax with 31 dwarf pugils.
tl;dr Cave Cherax can be caught with Dwarf pugils.
Can be gutted by Zaldon,via the quest Inside the Belly, for about a 25% chance at a Dwarf Pugil (an EX bait used to catch, most notably, Lik and Matsya - and when used with the Guild Key Item 'Mooching' gives extra time to reel in the difficult fish).