Are you shooting raw or jpeg? Raw is going to offer you a couple of benefits (assuming that camera has the option to save files in raw format). First, the larger bit density is going to allow you a greater range in both colors and luminance. Second, it's going to allow much greater ability in adjusting your white balance after the fact. . .which is really your best bet when shooting under blue light. Unfortunately, the camera's white balance settings just aren't going to be very good at faithfully reproducing shots under such abnormal lighting conditions. So my suggestion there would be to shoot raw using any white balance setting other than auto and adjust to your liking in Lightroom, Photoshop, etc.
The second issue comes in the extreme colors you're dealing with, where you'll have really high luminance in one color channel (sounds like the red channel in your case) and really low in another. You may have to underexpose the overall picture slightly to keep individual channels from getting clipped. If your camera will display a color histogram, that's the best place to check to ensure you're not clipping one of your color channels. Once again, if you're shooting in raw, you'll have more capability to recover clipped channels in post as well as adjust luminance for specific color channels in post.
If you can't capture in raw format, and the auto white balance setting isn't working, you should have an ability to set a custom white balance. Under blue LEDs, that could still be hit or miss, but you could give it a shot. You'll have to consult your user manual for the specifics on setting a custom white balance, but in general, take either a waterproof white balance card or something like a white 5g bucket lid, position it in the tank at about a 45 degree angle and use that to set your custom white balance.
Chances are I mentioned something you're not familiar with or didn't do a good job explaining it, so if any part of this (or all of it) doesn't make sense to you, let me know, and I'll try to explain it better.
