"I have an animal, it is a mouse."

Translation: Io ho un animale, è un topo.

[Bovinecow]

Is this correct English? Those are two simple sentences. Shouldn't it either be split into two sentences, joined by a conjunction such as "and", or have a semicolon joining them instead of a comma?

[nooomorgaux]

You are right. A comma is not the correct punctuation here. It should be a full stop or, like you said, a semicolon.

[kishkosh]

3 times in a row the same sentence. Ist that intentional?

[f.formica]

Perhaps it's waiting for you to deliver the punchline? :P