The lighting is from an on the tank LED strip (Fluval plant LED 48 inches long)

Camera Pentax K-1 (full frame sensor)
lens: Sigma 180mm macro
shutter speed 1/200
ISO 6400
aperture 7.1
flash - none

This ram was at the front of the tank in the shadow of the manzanita stump as I find the fish colors pop in the lower light as the light strip is on the back 1/3 of the tank.
I got as close to the tank as my minimum focusing distance would allow (about 10 inches) and shot.

I shot the image using the RAW file format
made a few quick adjustments in camera RAW

I then ran the image through Topaz Labs de-noise plugin for Photoshop to remove the noise, and then through Topaz Adjust to add a hint of HDR to give the fish a more 3-D look

I posted the image to facebook, then saved the image from facebook to my desktop (this is a quick way to resize the image to meet forum guidelines as the original file is over 10MB

Here is the image:
German Blue Ram.jpg