Most visible color on the sea bottom?

Yes, hi viz yellow knife for best visability on the bottom. The key reason why the yellow handles are used on all of these knives. Products - Sturgill Spearfishing

Why do you think most dive lights are yellow? Why are cones, saftey vests, and school zone signs colored the way they are? For the hi visability.

I know I and many other people have lost knives after I dropped them and couldn't find them in the murky water. Sure is nice to be able to see your knife down there and be able to dispatch your fish after you retrieve your knife.

Yellow and white are 2 very high visability colors, I only use white or yellow floatlines because they can be seen by dive buddies so they know where I am at or by boaters hauling butt around dive spots. I have heard of spearos being drag around after a prop wrapped up their floatline.

Quote from behslayer

I like Black/Grey for knives. I've lost a bunch, but it wasn't the knives fault. It was the Sheath. We need better Sheaths.

Would you want your knife to float?

That's a question I ask sometimes.

Floating, that's a thought. I could see some merit to that. In deep water, offshore.
For 90% of the diving I do, from shore, it would just get washed into the surf line and some tourist would either step on it and die or take it home. Or some body boarder would loose an eye.