I used strobes for all the blackwater pics, also the spotting light on the strobes, also the Sola spotting light.
f9, 1/200, ISO 200 on the camera, manual setting on the strobes most likely but too long ago to recall accurately, using a 60mm lens. I recall being surprised at how much the strobe spotting lights helped the focusing. Perhaps the different angles when using 3 spotting lights helps because they are not that bright compared to the Sola.
I took a lot more photos that night that I did not share on line, poor focus, composition, etc. Upon reviewing them again today, my best guess (and it is a guess) is that the portions of the creatures putting out light are also reflective of the same colors in those locations at the time they are displaying. I got the same colors in the pics that I was seeing in the field, if memory is accurate.
Hope that helps.