I went to the Sunshine Aquarium today. I quite enjoyed it, though it is actually pretty similar to other city aquariums I have visited in Europe.
The outdoor area was the part I liked most. It felt very calming after the agitation of the city. I counted 6 sea lions. There were 2 elderly otaria females and a young California sea lion in the show (which is simply a commented training session and features no information whatsoever about sea lions as a whole), and 3 California sea lions in the exhibit (a male in the overhead ring, and a mother and her pup in the area with only a small shallow pool). The male was a bit too big for the ring, it would work better with females. I also worry about the holding conditions of the ones that are in the show...
The indoor area is nothing special and is actually quite small. I really liked the weedy sea dragons which I had never seen before. As has already been said on here before, the pair of Baikal seals lives in a very small tank with no natural light. Interestingly, the fake ice in the middle of the water appears to be a floating structure, you can see it moving slightly at times.
I would say that a good third of the visitors were non-Japanese. But it was a weekday so not really a time for locals to go to the aquarium. I bought two hats, one with a frog logo and one with a flying penguin.