Only evolutionists deny the obvious. It is pretty obvious that such colorfullness would make them a target of other fish and that there are absolutely no other benefits to it.
Only creationists would make assumptions. Don't assume. I'm not going to say that you are wrong, because I don't know the answer. But, you have to give credence to the idea that colorful (or even glowing) fish exist, and can survive, simply because there are fish that glow, and there are colorful fish. The angelfish survives despite the fact that it is colorful. The Anglerfish survives despite the fact that parts of it glow. There are other fish in the sea that I do not talk about here that meet this criteria. So there is no reason to say absolutely one way or another without some work. One can guess, but that is it.