I’ve done this a few times, and it works well. I sprinkle the fish with a little chopped ginger & garlic, and maybe a splash of sesame oil.
All I would add is that my cook-times are half yours:
1 measure rice, 2 measures salted boiling water. Simmer very low, covered, for 10 minutes. Lay fish fillet on rice, re-cover, simmer for 5 minutes. Turn off heat & leave for 5 minutes. All the water will have been absorbed, so no draining is involved.
