PSA: If you can stand it, grind up fishing before [REDACTED]

In the Hydroplant zone, you have to dive deep and avoid and repulse a big monster to get some mats. If you have Fishing 15, the monster will ignore you.

As a bonus, if you've also got Cooking high enough to bake, you can make a baked dish out of Darkwater Fish that gives a massive buff to swim speed.