I've also seen the double layer sinks with fish in between. How anyone could care for fish in a setup like that is beyond me - totally ridiculous and cruel to the fish too. I'll have to admit that some of us Americans do go a little bit too far with coming up with ridiculous "inventions" that are not practical at all. I'd imagine the water in the sink or tub "fish layer" would get pretty scummy after time, especially when the fish die.