All depends on the lighting, camera being used, what lens, camera angle to the tank glass,
whether or not the photo was shot in RAW format and the post processed to correct for white balance, hand help vs tripod, lens filters, auto vs manual focus, etc...
So you see there are a lot of variables that come into play.
So to help you answer your question, the best course of action would be to ask the person that took the photo you liked, and ask them how they took the picture.
Camera, lenses, lighting, any post processing.