Get the Fin Gleam Helmet in Oblivion

This will tell you how to get the Fin Gleam helmet in Fight in Oblivion It lets you have night vision and life detect.

Steps

Fast-Travel to Anvil.
Walk to the waters edge, open up the map, and look for the small black island. The helmet is just off the coast on this island.
Find a rock on middle the island and position yourself west.
Now before you jump into the water, aim slightly south and turn on a night vision spell.
Jump into the water and swim in a direct line until you see the first patch of rocks.
Swim around these until you find a skeleton that is a lowing orb on its chest. As you get closer, you will see that it is a shiny glass Helm. This is your target, FIN GLEAM.
Quickly put it on, it has water breathing effects, and swim to the surface.

Enchant items with water breathing ability
If your character is an Argonian, you need not worry about your breath. Argonians have unlimited water breathing.
You can exploit the clear water glitch where you can see everything very clearly right between the surface of the water to spot the fin gleam easier.
Try to wield lighter cloths or armor, to help speed you up if you're a slow character.
Create water breathing potions.
Beat the Quest "Go Fish" at Lake Rumare to get the "Jewel of the rumare", a ring which gives you not only "water breathing on self" but also 4+ athletics
Watch your breath meter, don't die.

Save whenever you are on land, so if you run out of air and die you can restart at a nearby save.
Watch your Breath Meter.
Be patient.