On Feb 25, an update wiped out 7 tanks full of fish/dolphins/decorations/plants. I emailed Recharge Studios to ask if they were going to compensate players in some way (who, like me, spent actual money to buy Dolphin $). Their response was that they were exploring their options.
I've been doing a lot of buying and selling fish these past 3 weeks, to try and build my coins back up while I was waiting to hear from them. But nothing. And there is no way to build up my Dolphin $ to where it would need to be to replace everything that vanished, without spending more money, and I refuse to do that if Recharge Studios won't make good on the last bug.
So, as soon as all the fish/dolphins I have are adults, I'm packing it up and letting it lay dormant for a while. Too bad because it was a fun game but not worth the aggravation and certainly not worth throwing good money after bad. My advice is to play Fish farm or Butterfly Farm instead.