They're so cute! Water toys are really interesting like Aquapet or Mutsu. Right now at Target for $20, there's something called a Little Live Pets Dippers that I think would be pretty neat in an aquarium, (without live fish ofc) and you can even "feed" it. Here's a video if you're interested! Too bad Mutsu are quite hard or unaffordable to find, but this might help scratch that itch. I know I would have been pretty wild for this as a kid. I loved my Sea Monkeys though they were tiny live critters.