There used to be another type of cave before instead of the current Sea Crown Caves and the regular ones: The Tiger Plant Caves.
There were two Tiger Plant Caves and six Sea Crown Caves in total. They were all located reasonably close to each other and they contained an abundant amount of Tiger Plants, as their name suggests, making them very dangerous. They also contained Bleeders instead of Biters
The larger, crater-like cave used to be called the 'Overgrown Caves', due to the plants covering the walls, similar to the Kelp Forest Caves.
There are three caves that only have one type of Coral Shell Plate out of the three.