I don't think that will work. "か" cannot be used standalone the same way the question mark "?" is used in English (i.e., "pork?" "fish?"). It needs to be added to the end of a verb (in conjugated form), for example:
- the verb to be/exist: desuka (romanji), ですか (kana)
- the verb to eat: tabemasuka (romanji), たべますか (kana), 食べますか (kanji)
- the verb to go: ikimasuka (romanji), いきますか (kana), 行きますか (kanji)
So in your example, the question needs to be: ぶたですか and さかなですか。 In other words, translated into English, it can't just be "pork?" "fish?" it needs to be "IS this pork?" "IS this fish?".
However, you inadvertently bring up another point, which is "short form" Japanese or "casual form." which you might not learn just yet if you are a beginner. In short form (which is how most conversational Japanese is spoken, for example, between friends), you can in fact drop the "desuka / ですか" altogether, so that the question really does become "pork?" "fish?". In Japanese it would be "ぶた?”、”さかな？”, with the rising intonation at the end, as you indicated.