The Deep Dark Ocean Dimension

The Deep Dark Ocean Dimension is made of three layers which are stacked one on top of the other. 

The upper layer is where most players will spawn when first entering the dimension. At the top of this layer you can find portals going back to the overworld as well as Ocean Crystal ore. Most neutral fish also spawn in this layer.

The Middle layer is between the upper and lower layers. This layer is a upside-down forest overlooking the lower layer.

The final layer is the lower layer. This is the most dangerous of the three layers. In this layer you can find piranhas, guardian squids, deep ocean dungeons, and seagem ore.

Piranha: The Piranha is a very annoying swarming fish that does very little damage but attacks as a unit. They can be found in groups up to 18.

Guardian Squid: The guardian squid is a huge creature that spawns near treasure on the ocean floor. These creatures act as a sort of mini-boss.

Manta Ray: This creature is a water mount, which means it can be tamed and rode on. it's favorite treat is deep water melon but it can live off of just ligno nuts. While riding the creature, look up to rise and look down to sink.