Hello.  Thank you for taking a moment to read my question.

My husband and I own a fishing boat in Costa Rica.  Last nite (March 29, 2013) we turned the underwater blue lights on outside of the boat.  About an hour into darkness the blue runners came..  The started acting very strange!  They began to circle around in an almost desperate way rising to the top of the water.  Then they would jump out of the water and splash around almost like they were trying to get air into their systems... It was so odd.  I mean there were hundreds of them doing this on both sides of the dock.. At the time, my husband and I said we thought that something was very wrong with them.  Then, when we turned off the lights they began to jump out of the water by the hundreds (literally)... it was crazy.  We both agreed that by morning we would see a lot of dead blue runner fish... and we did.  This morning there are many many dead blue runners here at the marina.  Do you have any idea what happened to them?  This was the most odd behavior we have seen in any fish.  Thank you!  karen

Sorry that nobody has a good answer to this.

As I'm sure you know the lights will have attracted the fish, probably allowing them to feed as they are visual predators. This is just pure speculation really - but I wonder if they also attracted something bigger than feeds on blue runners. The panicked behaviour, circling and jumping sounds a bit like they were being forced into a bait ball by a predators below. As I say this is just speculation though !