The entrance is in Ashenvale at the north end of Zoram Strand. If you come in from Darkshore along the path to the west, it leads directly to the pool that leads to Blackfathom Depths. Watch out for stealthed and invisible satyrs among the naga. Bring some water breathing potions, or a warlock; you can do it all without, but a couple of areas will be tough if you forget.
Je’neu Sancrea (Horde) – The Essence of Aku’Mai
Je’neu Sancrea (Horde) – Allegiance to the Old Gods (II)
Damp Note/Blackfathom Tide Priestess (Horde) – Allegiance to the Old Gods
Gerrig Bonegrip, Ironforge – Knowledge in the Deeps
Dawnwatcher Shaedlass, Darnassus – In Search of Thaelrid
Gershala Nightwhisper, Darkshore – Researching the Corruption
Argent Guard Manados, Darnassus – Twilight Falls
Argent Guard Thaelrid, Darnassus – Blackfathom Villainy
Doan Karhan, Barrens – The Orb of Soran’ruk (warlock only)
As usual, Horde get a few extra quests in the instance.
The corrupted brain stems drop from every naga killed, including those outside the instance. The Argent Guard is in a cove reachable only by swimming underwater; you will see a quest marker when you get near. The manuscript for Gerrig is in the first niche to the right in the first pool room, in a chest.
Behind the named murloc is a clickable stone – this gives a useful buff to int, spirit and frost damage.
After killing Kelris, light the four bowls on the corner of the statue ONE AT A TIME. After each flame is lit, a wave of mobs will come out of the alcoves on each side, and after the last wave the doors open. Underneath Kelris is the Forgotten Pool – to the north, underwater, is a named thresher.
Once you have killed Aku’mai, a dwarf appears; once he has finished his speech, you can either click on him for a port to Darnassus, or click on the altar to be ported back to the entrance pool in Ashenvale.
Bosses
Aku’mai – Leech Pants (cloth legs), Moss Cinch (leather waist), Strike of the Hydra (two handed sword).
Baron Aquanis – Strange Water Globe (starts a quest, Horde only).
Gelihast – Algae Fists (blue mail hands), Reef Axe (two handed axe).
Ghamoo-ra – Tortoise Armor (blue mail chest), Ghamoo-ra’s Bind (cloth waist).
Lady Sarevess – Naga Battle Gloves (blue leather gloves), Darkwater Talwar (one handed sword), Naga Heartpiercer (bow)
Old Serra’kis – Bite of Serra’kis (blue dagger), Glowing Thresher Cape (blue)
Twilight Lord Kelris – Rod of the Sleepwalker (blue staff), Gaze Dreamer Pants (cloth legs)