How to recreate this scene?

[WALP]

Then start checking all of the things in the script and level and not just the water plants and fish. Look in the level settings and see if there anything set different than default, try ticking on and off to see effects. Look at lights, particle systems, areas placed around(including script areas), etc. as long as you use your head you have just as great odds at figuring it out as we have, and you might as well get used it if you want to mod SOMA. If find get anything specific you can't get to work correctly, that's when you ask for help.