Sorry Balckice but you really have to be nuts. It's true there are no real penetration options for the Nichi Asu Maru (sometimes referred to as the Kuantan Wreck) but it is an absolutely fantastic site brimming with wonderful creatures. I've never been disappointed on a dozen or so dives there. The hundreds of morays at the site is enough to keep me interested but you can often also see marbled rays, schools of large cobia, several shovel nosed rays, honeycombed rays, turtles, huge groupers, massive helmet crabs, stone fish, lion fish, leopard sharks..... Are you sure you were at the right wreck???? Most of the time at the Seven Skies, you can only see some bat fish, more bat fish and schools of bat fish.
Incidentally, the Nichi Asu Maru is the perfect divesite for Nitrox diving. Because of the flat sandy bottom, you can't get deep enough for toxicity to be a problem but at 85' you can really extend you bottom time if you are not a heavy breather.
Finally, yes, that is oil that is leaking from the wreck. Avoid swimming through it or you will never get you gear cleaned. It's one of the hazards of the wrecks but every wreck has things you have to be careful of.