This category is for aquatic creatures, as described on p. 306 of Monster Manual v.3.5. Such creatures almost always are superb swimmers and can breathe underwater. Unless they are also amphibious, they cannot also breathe air.
This category has the following 3 subcategories, out of 3 total.
Pages in category "Aquatic creatures"
The following 40 pages are in this category, out of 40 total.