I think "I bite fruit" should be accepted. This is an instance in English where an article is not necessary. Do any agree?
No. You're translating the High Valyrian into English, not creating an English sentence. In English, "I bite fruit" gives the impression that one is biting into a mass of fruit or many fruits. That is not a possible interpretation of Gerpe angon. That is your English interfering with the proper understanding of the High Valyrian. Gerpe is—and must be—singular.