For those who may be interested :

Photo taken in raw. Opened in Photoshop Elements 11 after minor adjustments.

In PSE 11 used Lighting - levels - ticked on black and used eye of fish as black standard.

Noise reduction in various stages to remove spots

Used unsharp mask (minimum)

Slightly increased brightness.

Nikon D 5200 Aperture mode ISO 1250 1/40 sec f 5 62 mm