Thank you Mannie
today I can ... I don't know the words in english... kick me by myself...
I rendered in a very good quality, rendertime was over 10:30 hours. In the meantime our little son and I baked over 180 cookies... then I saved, closed vue and forgot my difficults in saving .jpg files in vue 8.
As .jpg it looks bad for me with this artifacts for example on the fishes in the foreground. It looks like too much sharping or something else...
In Vue 6, 7 and 7.5 there was a window with the question about quality for saving an image as .jpg. In Vue8 there is no question, vue save... and I don't know what or where the settings for the quality were.
Now I render this Image again sience hours and then I save as .tif. That looks after opening in Photoshop very good (top image I had saved as .tif and it looks after first postwork and sharpen better then this one).
Here are the .jpg render... quality in Vue 8 as very high.. but the result because saving as .jpg...

This is the finish version, saved as .tif and after a little postwork. If I think about the rendertime and the result, then the image in my first post with a rendertime from only 15 minutes more as good enough for me. I like the caustic effect. It was a little bit difficult to lighting the fishes in background, because the fishes placed as eco-system.
