diff --git a/rllib/models/tf/complex_input_net.py b/rllib/models/tf/complex_input_net.py
index 8bc691e24..235701854 100644
--- a/rllib/models/tf/complex_input_net.py
+++ b/rllib/models/tf/complex_input_net.py
@@ -49,8 +49,9 @@ class ComplexInputNetwork(TFModelV2):
             # Image space.
             if len(component.shape) == 3:
                 config = {
-                    "conv_filters": model_config.get(
-                        "conv_filters", get_filter_config(component.shape)),
+                    "conv_filters": model_config["conv_filters"]
+                    if "conv_filters" in model_config else
+                    get_filter_config(obs_space.shape),
                     "conv_activation": model_config.get("conv_activation"),
                     "post_fcnet_hiddens": [],
                 }
diff --git a/rllib/models/torch/complex_input_net.py b/rllib/models/torch/complex_input_net.py
index 2b9601947..db72d6c9e 100644
--- a/rllib/models/torch/complex_input_net.py
+++ b/rllib/models/torch/complex_input_net.py
@@ -55,8 +55,9 @@ class ComplexInputNetwork(TorchModelV2, nn.Module):
             # Image space.
             if len(component.shape) == 3:
                 config = {
-                    "conv_filters": model_config.get(
-                        "conv_filters", get_filter_config(component.shape)),
+                    "conv_filters": model_config["conv_filters"]
+                    if "conv_filters" in model_config else
+                    get_filter_config(obs_space.shape),
                     "conv_activation": model_config.get("conv_activation"),
                     "post_fcnet_hiddens": [],
                 }