Deep(er) Emerald Oceans

A cavern variant of oceans reaching to or below y=0, filled with holes connecting to regular oceans. There would be green ocean fog, horn and tube corals, and a new Emerald Kelp plant. They could be used to craft with pufferfish then feed to nautilus to have venomous special effect, hitting entities would give the enemies venom. For zombie nautilus, being hit would give enemies venom. Add an emerald variant of glowsquids (same entity) that spawn in this biome only (drops same item). Add a new Emerald Garden structure which would be home to emerald glowsquids and Clams, a neutral mob. It would be made of Emerald Kelp Bricks, Emerald Kelp Block, Glow Emerald Kelp Block, Polished Dripstone Blocks, horn and tube corals, and Copper bars. 4 Emerald Kelp and 5 glow inc sac would give a new Glow Emerald Kelp Block block. 9 emerald kelp for bricks, 4 for Emerald Kelp Block. Clams would have Heart of the Sea inside.