Hey there. I must say I really like the overall color scheme used in the sky; it greatly enhances the atmosphere in this case. The creature from the abyss (if you may ;) ) is really well made, especially the detail that went into the illumination of the creatures scales.
There's a feel of lovecraft here, it may or may not be intentional but it definently carries that feeling.
I have something I wonder though, when looking at the light emenating from the creatures mouth that enligtens the water infront of it the source of the the light makes sense, however shouldn't it be a little bit darker in the area under the bridge? The light doesn't seem to extended around it but in front of it, hence my question.
To summarize: In short great work with the overall atmosphere and setting the fit together really well, especially with the scales you did an excellent job.