(Excuse my C++ background, I'm sure Java calls these things by different names... but anyway...)
With the latest release, Java now supports a concept similar to C++ templates. One big win with this is the ability to avoid creating classes that have no type safety, like generic collection classes. The warning you are getting is telling you that you are using one of these generic collection classes, when you should be creating a collection to hold the exact type of thing you want in the collection.
ArrayList<CFish> fishList = new ArrayList<CFish>;
fishList.add(new CFish("Salmon")); // is good.
fishList.add(new CBird("Hawk")); // won't compile