The Nightmare mudlib supports fishing!  And creating a room that allows fishing
is very easy.  Basically, it is just like building a regular room, except
instead of inheriting /std/room, you inherit /std/pier
Other than that, you add the following function calls:
(some of these are optional, and marked as such)
 
void set_max_fishing(int x);
example: set_max_fishing(10);
This function sets the most players which can be fishing in the room at the
same time.  You must set this number, or no one will be able to fish.
The number you choose should depend upon whether the room is a small
fishing hole, or a huge jetty on the ocean.
 
void set_chance(int x);
example: set_chance(4);
A number between 1 and 20 which defines how good of a fishing spot
the area is.  20 means the fish bite like crazy, 1 means they rarely bite.
This is a necessary function to call as well.
 
void set_max_catch(int x);
example: set_max_catch(15);
This sets how many fish are in the room every reset (the fish population).
15 is a lot :).  This is a necessary function call.
 
*** Optional ***
void set_fish(mapping borg);
example: set_fish( ([ "catfish": 5, "mackeral":10 ]) );
This allows you to customize the fish that players catch in the room.
There is a default of 4 fish.  This function replaces the fish which
are default.  The structure of the mapping is as follows:
       ([ fish_name: strength, fish_name: strength ])
Where fish_name is a string which is the type of fish being caugh, and
strength is how good of a healer the fish is (It is exactly the
same variable as strength in food).  Also, the better the fish is at
healing people, the more likely it is to break the player's pole.
 
*** Optional ***
void add_fish(string str, int x);
example: add_fish("catfish", 5);
This function call just adds a fish to the list of fish in the room;s
fish population.  The first argument is the fish type, and the second is the
healing strength of the fish.