I'm sure everyone's seen the announcement about the immortal fish - and thus most of the A-list tanks - being removed shortly.
They are testing their script for removal of these fish. My tank was one of the test cases. No, this isn't a secret, the thread for feedback on the test runs is in the new Aquarium Discussion subforum, right out in public where everyone can see it.
This is going to affect the amount of gold going into the Gaia economy, especially since Phin Phang isn't expected to reopen for a "a few weeks" (see
announcement here), so unless they're not actually going to run this script until Phin Phang is set to open, there's going to be a gap between when the tanks empty and when it is possible to refill them at any level. (Whether the tank owners will refill them or not is another issue, not germane to this posting.)
This means it is very likely there will be fewer Booty Grab games available, and thus less gold. Plan accordingly.
(I would strongly prefer that people not argue about whether this is a good thing or not. That's not the issue. The issue is that this is happening, it is almost certainly going to affect the Gaian economy, and that means it changes the buying/selling/investment environment. Which means as buyers/sellers/investors, you need to think about how it's going to affect YOU and plan accordingly.)