ATLANTICA

This water world doesn't have any Heartless except those that can survive under it. Therefore, all you'll find here are Atlantica specific Heartless, Search Ghosts and after Hollow Bastion, some Darkballs.

SEA NEON
Items Dropped: Ether (1%), Frost Gem (6%), Blizzaga Ring (0.5%)

Place	HP	EXP
Before Rescue	24	10
After Rescue	90	75

Defense: Though these Heartless aren't fast at all, they are like the Shadows of the land-based worlds. They appear in groups of 4 or more.

Strategy: Since Target-lock is pretty essential in Atlantica, use it to lock onto these Heartless and defeat them quickly.

SHELTERING ZONE
Items Dropped: Ether (4%), Frost Gem (10%), Blizzaga Ring (1%)

Place	HP	EXP
Before Rescue	60	24
After Rescue	300	180

Defense: If you reduce the Sheltering Zone's HP down to 0 by physical attacks, it will dissolve into 4 Sea Neons.

Strategy: Though these Heartless are just larger versions of Sea Neons, they do have that habit of splitting into more Heartless. To prevent that, use Magic spells to take it out.

SCREWDIVER
Items Dropped: Hi-Potion (4%), Thunder Gem (6%), Thundaga Ring (0.5%)

Place	HP	EXP
Before Rescue	48	18
After Rescue	150	120

Defense: These Heartless are pretty agile in the water, and their charge attack is fairly quick.

Strategy: Take these on one at a time, and don't stay on the same level for too long before they charge you with their tridents. A couple of good combos can take them out, but make sure to swim up and down to different levels to dodge them.

AQUA TANK
Items Dropped: Mega-Potion (8%), Thunder Gem (10%), Thundaga Ring (1%)

Place	HP	EXP
Before Rescue	90	36
After Rescue	480	300

Defense: These lanterfish Heartless have Screwdivers to back them up usually, and they use Thunder spells to protect itself.

Strategy: They aren't too fast, but Aqua Tanks can charge you. Take them out first and they'll release the Screwdivers they are carrying.