Thanks guys, it was a great trip for sure and glad the pics came out good to

Their reaction to divers can be quite variable, but mostly reflect the fact that big cod are usually the area's top predator. If you hang out in a school of bait they'll often come to inspect you after a fairly short time. Also, in dark water they tend to almost light up as their so brightly coloured compared to other fish or the surroundings, so they're often very easy to spot. Smaller fish can sometimes be more scittish. In pressured spots it can be different. I've spotted, but failed to get even close to shooting range on huge (probably resident) cod (15kg+) in certain spots where 5-10 kg fish can sometimes be had on every drop.
They're usually poor fighters, but one out of five-ten fish will put up a decent first run and may tug your line a little. Most will just shake about and try to loose the spear, so they're usually very easy to get to the surface.