Thank you, folks!
Rob, unfortunately, I had no much free time and money for this Hobby(Aquatic-photography)…:-(
So, I didn’t change/update any of my equipment through the last years…it’s all the same:
EF 50 mm/f2.5 Compact-Macro lens+ Two External Flashes - Canon Speedlite 580EX and 430EX
My usual settings:
Shutter Speed: 1/200 seconds
Aperture Value: f/11-22(dependent on the fish specific and fishes position)
ISO Speed Ratings: 100-400(dependent on the fish and tank interior specific)