Ok I went back to fish some crocodilos with the following set up:
noddy ring and a puffin ring.
(Yes I ended up buying a puffin ring for 800k.) ><
You can actually catch them without a puffin ring but you just need to practice reeling them in as your rod will flail around a lot.
The puffin ring gives you more time to work the crocodilos HP down and works just as well for Gugrusaurus and Liks.
Noddy ring reduces a chance of monsters biting at your line but you could probably sub something else there if you weren't bothered about that.
(Pelican ring for skill ups, Albatros ring if you want to add even more of a chance of reeling in a big fish or any of the other ring types from moblin maze mongers: heron ring / seagul ring.)
I realize I am giving myself some advice here but it only comes with experience and I'm making this post incase others feel like having a go at this fish.
Lu Shangs Fishing Rod obtained: Feb 2005
Maat's cap Obtained: Saturday 31st July 2010
Ebisu Fishing Rod Obtained: Sunday 8th August 2010