diff --git a/aider/coders/__init__.py b/aider/coders/__init__.py
index bf9163328..19d12b0d7 100644
--- a/aider/coders/__init__.py
+++ b/aider/coders/__init__.py
@@ -1,5 +1,6 @@
 from .base_coder import Coder
 from .editblock_coder import EditBlockCoder
+from .editblock_fenced_coder import EditBlockFencedCoder
 from .editblock_func_coder import EditBlockFunctionCoder
 from .single_wholefile_func_coder import SingleWholeFileFunctionCoder
 from .udiff_coder import UnifiedDiffCoder
@@ -9,6 +10,7 @@ from .wholefile_func_coder import WholeFileFunctionCoder
 __all__ = [
     Coder,
     EditBlockCoder,
+    EditBlockFencedCoder,
     WholeFileCoder,
     WholeFileFunctionCoder,
     EditBlockFunctionCoder,
diff --git a/aider/coders/base_coder.py b/aider/coders/base_coder.py
index 45d67b1ed..74122ac33 100755
--- a/aider/coders/base_coder.py
+++ b/aider/coders/base_coder.py
@@ -69,7 +69,12 @@ class Coder:
         from_coder=None,
         **kwargs,
     ):
-        from . import EditBlockCoder, UnifiedDiffCoder, WholeFileCoder
+        from . import (
+            EditBlockCoder,
+            EditBlockFencedCoder,
+            UnifiedDiffCoder,
+            WholeFileCoder,
+        )
 
         if not main_model:
             main_model = models.Model(models.DEFAULT_MODEL_NAME)
@@ -102,6 +107,8 @@ class Coder:
 
         if edit_format == "diff":
             res = EditBlockCoder(main_model, io, **kwargs)
+        elif edit_format == "diff-fenced":
+            res = EditBlockFencedCoder(main_model, io, **kwargs)
         elif edit_format == "whole":
             res = WholeFileCoder(main_model, io, **kwargs)
         elif edit_format == "udiff":
diff --git a/aider/coders/editblock_fenced_coder.py b/aider/coders/editblock_fenced_coder.py
new file mode 100644
index 000000000..2f612c754
--- /dev/null
+++ b/aider/coders/editblock_fenced_coder.py
@@ -0,0 +1,11 @@
+from ..dump import dump  # noqa: F401
+from .editblock_coder import EditBlockCoder
+from .editblock_fenced_prompts import EditBlockFencedPrompts
+
+
+class EditBlockFencedCoder(EditBlockCoder):
+    edit_format = "diff-fenced"
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.gpt_prompts = EditBlockFencedPrompts()
diff --git a/aider/coders/editblock_fenced_prompts.py b/aider/coders/editblock_fenced_prompts.py
new file mode 100644
index 000000000..07a8fbbab
--- /dev/null
+++ b/aider/coders/editblock_fenced_prompts.py
@@ -0,0 +1,95 @@
+# flake8: noqa: E501
+
+from .editblock_prompts import EditBlockPrompts
+
+
+class EditBlockFencedPrompts(EditBlockPrompts):
+    example_messages = [
+        dict(
+            role="user",
+            content="Change get_factorial() to use math.factorial",
+        ),
+        dict(
+            role="assistant",
+            content="""To make this change we need to modify `mathweb/flask/app.py` to:
+
+1. Import the math package.
+2. Remove the existing factorial() function.
+3. Update get_factorial() to call math.factorial instead.
+
+Here are the *SEARCH/REPLACE* blocks:
+
+{fence[0]}
+mathweb/flask/app.py
+<<<<<<< SEARCH
+from flask import Flask
+=======
+import math
+from flask import Flask
+>>>>>>> REPLACE
+{fence[1]}
+
+{fence[0]}
+mathweb/flask/app.py
+<<<<<<< SEARCH
+def factorial(n):
+    "compute factorial"
+
+    if n == 0:
+        return 1
+    else:
+        return n * factorial(n-1)
+
+=======
+>>>>>>> REPLACE
+{fence[1]}
+
+{fence[0]}
+mathweb/flask/app.py
+<<<<<<< SEARCH
+    return str(factorial(n))
+=======
+    return str(math.factorial(n))
+>>>>>>> REPLACE
+{fence[1]}
+<<<<<<< HEAD
+""",
+        ),
+        dict(
+            role="user",
+            content="Refactor hello() into its own file.",
+        ),
+        dict(
+            role="assistant",
+            content="""To make this change we need to modify `main.py` and make a new file `hello.py`:
+
+1. Make a new hello.py file with hello() in it.
+2. Remove hello() from main.py and replace it with an import.
+
+Here are the *SEARCH/REPLACE* blocks:
+
+{fence[0]}
+hello.py
+<<<<<<< SEARCH
+=======
+def hello():
+    "print a greeting"
+
+    print("hello")
+>>>>>>> REPLACE
+{fence[1]}
+
+{fence[0]}
+main.py
+<<<<<<< SEARCH
+def hello():
+    "print a greeting"
+
+    print("hello")
+=======
+from hello import hello
+>>>>>>> REPLACE
+{fence[1]}
+""",
+        ),
+    ]
diff --git a/aider/models.py b/aider/models.py
index dc7092d2c..24d001eee 100644
--- a/aider/models.py
+++ b/aider/models.py
@@ -154,13 +154,13 @@ MODEL_SETTINGS = [
     # Gemini
     ModelSettings(
         "gemini/gemini-1.5-pro",
-        "whole",
+        "diff-fenced",
         use_repo_map=True,
         send_undo_reply=True,
     ),
     ModelSettings(
         "gemini/gemini-1.5-pro-latest",
-        "whole",
+        "diff-fenced",
         use_repo_map=True,
         send_undo_reply=True,
     ),