The Limited UGC "Aquarium Egg" has ran out of copies 2 hours ago. There were a total of 10,000 copies and unfortunately at this time no one is able to obtain this avatar item anymore. If you really want this item, you will have to wait 30 days and purchase it when a user is re-selling the item.
Try joining a private server and see if that solves the problem. If not, start the Data Recovery Tool which can be found in the game settings under the "game" category. If you still have an issue join the Fishing Simulator Discord server linked in the description and open a ticket.
2:14 I'm at 49 eggs collect and this egg is my last egg but the problem is that the wandering merchant has arrived so getting this egg is a waiting game