"Such a fish does not drink beer."
Translation:Sådan en fisk drikker ikke øl.
This is grammar that I am a little hazy on, but I think because "sådan" which would normally warrant an invertion, specifically modifies "en fisk". It depends on what "sådan" is meant to make a comparative statement about. If we invert the subject and the verb, it would also change the meaning of the sentence.
"[Sådan en fisk] drikker ikke øl." - [A fish like this/that] does not drink beer.
"[Sådan drikker] en fisk ikke øl." - A fish [doesn't drink] beer [like that].