This is the sort of comment that makes me aware of how alien even very similar cultures can be. I'm Irish and I grew up there. I had never defrosted anything in a fridge before moving to Shanghai. It was all either countertop defrosting or hot water. I wouldn't defrost fish in hot water because it'll cook or let it defrost at room temperature for more than an hour which should be plenty for most fish. If room temperature where you live is above 20 or so degrees you probably shouldn't counter top defrost unless you can check it regularly to see if it's done and

Hot water isn't really that bad for bacterial growth. Lukewarm water is the enemy but even that's fine as long as you cook the meat within half an hour of taking it out of the fridge for defrosting. If you're taking longer z than half an hour that's a substantial cut off meat and you really should be able to plan a day ahead.