Aside from the fact that the better camps like Oasis and that crab alley slightly south of it have been nuked via mob removal (or OWNM placement)?
Zaroua wrote:
Crabs are god awful at low levels. High HP and defense, a defense buff, a magic defense buff, Metallic Body (aka Stoneskin) and a very strong STR debuff. What usually ends up happening when fighting a crab is that it puts up is defense buff and cuts down your melee damage by about 75% and then you spend 2-3 minutes having your 2h melee hitting for 5 dmg and your 1h or dual wield melee hitting it for 0 (without Metallic Body). If you have a BLM, it'll either run itself OOM from being the only one being able to do damage to the crab or it'll pull aggro off of the tank because a tank hitting for 0 doesn't generate a lot of hate.
Flies and sheeps are quite good though, especially if you have a PL to handle the AoE healing or have a group that won't feed the flies too much TP. There's a spot around I-7 with more mobs flies/sheeps than any group can handle that will last you to from 16 to 18-19.
This. If melee are geared correctly they might* still be able to damage a crab. But there's not exactly a ton of options available at level 13 anyway. Bards aren't always going to be available, neither are 2 BLM to ensure you can kill them in an adequate amount of time. Flies and sheep almost necessitate either a PL or a whm, and at that level cure/curaga spam will leave a whm tapped in 1 or 2 fights unless they're rocking one hell of an MP+ setup.