I have many models in my project, and some other classes just need the class declaration and pointer type aliasing. It does not need to know the class definition, so I don't want to include the model header file. I extract all the model's declaration into one file to let every classes reference one file.

model_forward.h

class Cat;
typedef std::shared_ptr<Cat> CatPointerType;
typedef std::shared_ptr<const Cat> CatConstPointerType;

class Dog;
typedef std::shared_ptr<Dog> DogPointerType;
typedef std::shared_ptr<const Dog> DogConstPointerType;


class Fish;
typedef std::shared_ptr<Fish> FishPointerType;
typedef std::shared_ptr<const Fish> FishConstPointerType;

enum CatType{RED_CAT, YELLOW_CAT, GREEN_CAT, PURPLE_CAT}

enum DogType{HATE_CAT_DOG, HUSKY, GOLDEN_RETRIEVER}

enum FishType{SHARK, OCTOPUS, SALMON}

Is it acceptable practice? Should I make every unit, which needs a class declaration, depends on one file? Does it cause high coupling?

Or I should put these pointer type aliasing and enum definition inside the class back?

cat.h

class Cat
{
    typedef std::shared_ptr<Cat> PointerType;
    typedef std::shared_ptr<const Cat> ConstPointerType;

    enum Type{RED_CAT, YELLOW_CAT, GREEN_CAT, PURPLE_CAT}
    ...
};

dog.h

class Dog
{
    typedef std::shared_ptr<Dog> PointerType;
    typedef std::shared_ptr<const Dog> ConstPointerType;

    enum Type{HATE_CAT_DOG, HUSKY, GOLDEN_RETRIEVER}
    ...
}

fish.h

class Fish
{ ... };

Any suggestion will be helpful.