Video at night with no lights

I am gearing up for field research beginning this fall. The goal is to grack and video large schools of bonefish as they move offshore to spawn. On the one hand, this is great because they spawn offshore in clear, tropical water. On the other hand, this is a huge challenge because they spawn at night (though usually on a full moon), at about 60m depth. I am searching for input on options for video under these conditions. I can’t use flood lights because this will spook the fish (a ball of 10,000 silver, 5 to10 pound fish in the open ocean at night is already spooky without lights). I have been thinking about perhaps revising the camera on a Trident to infrared. That would void the warranty, but if it works it would be worth the risk. Any ideas, input, advice appreciated.

Fish are cold blooded so probably won’t show on infra red as they emit negligible heat.

Also, infrared light is heavily attenuated in water so it wouldn’t work for that reason either. This is a very cool mission! I wish I could think of a quick and easy solution for you. Have you seen the episode in Blue Planet II where they use extremely light-sensitive cameras to film rays swimming at night through bioluminescent plankton? Nature is amazing!!!


Thanks Jim and Eric. An ROV-mounted IR light would fix the cold-blooded fish challenge. But you are correct about IR being attenuated quickly in seawater - The ROV would have to right on top of the school of fish. The appeal to IR is that bonefish can’t see it. They do pretty well detecting the visible portions of the light spectrum.
The more I look into it the more I think I need to find a way to get super-sensitive cameras that get me an image in low light conditions.
It is a very cool (and challenging) mission! When we’ve tracked the school offshore at night, our boat has been circled by tiger sharks a couple of times, so no way we’re putting people in the water. If we can get footage, it will be the first, and will tell us a lot about their reproductive behaviors.
So I guess now I have to track down some of the experts who film things like the Blue Planet episodes.
Thanks for the input.