Re: Planning a trip to Hungary any tips?
This won't be the best information, but will give you an educated guess.
I have an acquaintence who grew up in Hungary many years ago. I asked him about your question.
He recalls a dozen or so species in the Danube in the Budapest area. Unfortunately, he doesn't know what the English names would be. He does recall carp, sturgeon, catfish, as well as others.
We both live in Kansas on the Missouri River, which is very muddy and mainly carp, catfish, sturgeon, etc. I know that he used to live in Colorado near the trout waters of the Arkansas River. I asked him to compare the Danube to both of these and he said it's somewhere in between. It's neither clear trout water nor the "Muddy Mo." but more greenish and big enough to handle barges for most of its length. I got the impression it might be comparable to the Missouri River as it runs through the Dakotas or the upper portions of the Ohio around Pittsburgh, PA. I'm guessing you could might get into species that inhabit those waters.
He did say that Budapest is very much like Kansas in terms of climate. In other words, warmwater.
I hope you can use this somehow. Tight lines!