What fruits cannot be put into jello?

There's no fruit that you *can't* put into jello, it's more about how the fruit will behave. Some fruits are better suited than others due to:

* Texture: Some fruits, like berries and grapes, hold their shape well in jello, while others, like bananas and peaches, will become mushy.

* Flavor: Some fruits, like pineapple, have an enzyme that can prevent jello from setting.

* Appearance: Some fruits, like kiwi, can make the jello appear cloudy.

Here are some tips for using fruit in jello:

* Use firm fruits: Berries, grapes, cherries, and diced apples hold their shape well.

* Use canned fruits: Canned fruits are often already in syrup, which can help prevent them from becoming mushy.

* Add fruit after the jello has set: This will help prevent the fruit from sinking to the bottom.

* Use a little pineapple: Adding a small amount of pineapple to jello is usually fine, just don't use too much.

Ultimately, experiment and see what you like best! You might find some unexpected combinations that work well.