Have you tried the Fish Tycoon lists provided by Carla here to determine what "level" egg you are searching for?

The Wasp Grouper doesn't "work" all the time. The description of the fish reads: "With this fish in your tank, pregnant fish have a chance of producing a baby not related to either parent!" which does not guarantee a different offspring each time. Did you also check to be sure you had room in your tank for more babies? Good luck!

As I'm sure you know, time traveling can have many unpredictable and often negative effects on a game. It also affects every application on a device, including system applications.