Instead of buying a fish bowl you could buy a much larger fishtank and populate it with different fish. Most fish would simply be store bought but there could be some achievement fish and even special event fish. (like a skeleton fish for halloween) The fish tanks would have a size limit and maybe specific fish would have specific traits such as being more active at different points throughout the day or being incompatible with other fish.
Perhaps you could even leave a fishing rod at the board walk and be alerted when it gets a bite giving you a couple of minutes to tend to it. Fish caught are of different rarities and differ based on what time you’re fishing.
Maybe there could be terrariums for other animals such as beetles or hermit crabs.
There could even be an achievement section for fish collecting such as having all the animals in a category and the ultimate achievement of obtaining every fish for the collect-a-thon player in all of us.
