I agree, this work is beautiful. The roof is brilliant and the overall atmosphere of the moc is peaceful; exactly like I would expect a Japanese temple to feel. The bridge is also quite ingenious, heck, so is the whole thing! Thanks for posting this, it's a great work.
The fish appear to be on a disc that spins and makes them swim in a curved pattern. The roof is made of 1x1s each twisted at an angle to the one before them. The 1x1s are also bent to shape the roof with an roundish shape.
I am a big fan of the roof technique. I like the look of the rocks at those angles but have to say I don't think it is worth it when you can see the hinge brick from the side like that. Perhaps if he hid the hinge brick back one layer and hid it with cover bricks... then I would like it a lot more.