Kagoshima - aquarium or zoo?

I have to kill half a day in/around Kagoshima until a 4pm boat for Yakushima later this month. Which facility is better - the Kagoshima Aquarium or the Hirakawa Zoo?
I've already been to Sakurajima, Shiroyama Park, the garden, etc. Was thinking of going to Chiran but something tells me the buke yashiki gardens won't be as spectacular as they make them sound... or am I wrong? The kamikaze museum sounds depressing, unless I'm wrong again. So I'm tossing between the zoo and the fish.

I am a resident of Kagoshima and have been both for several times. Both are not so bad, but there might be better aquariums and zoos in Japan. I enjoyed every time, so you will not be deeply disappointed, I hope.

It takes about 1 hour by bus to the zoo while the aquarium is in a walking distance from the city center. The aquarium is air-conditioned. There are some other places to stroll around, such as Tenmonkan, Reimeikan museum (now exhibiting Machu-Picchu) etc.

Therefore, my recommendation is the aquarium, but of course it depends on your preference :). Have a nice trip!

Thanks! Yeah, I was thinking more of the aquarium too, Reimeikan could be another good addition. :)