Answer:
All the three elements which are talking animals, goldfish and rule of three include in the story.
Step-by-step explanation:
In Etgar Keret's "What, of This Goldfish, Would you Wish?", all the three elements which are talking animals, goldfish and rule of three include in the story.
The the talking animal would be the goldfish. And the rule of three would be the three wishes that Yoni asked people if they found a talking goldfish that granted three wishes.
The rule of three could also be implied to Sergei who was actually granted three wishes by the magic goldfish.