Unfortunately, the gars and pikes are infesting a few of the neighborhood ponds. I had no idea they were so dangerous: imagine my surprise when one of them ate my woodchopper after he had wandered to close to the shore to chop down a tree.
Their attack itself isn't so dangerous anymore (it used to be, since they would quickly become legendary swimmers, with all the stats that implies), but the fact that they drag you into the water and the fact that natural bodies of water have sheer vertical walls.
Anywhere that dwarves may be working near water and hostile creatures, you should probably cut ramps into the riverbank.
That sounds interesting, I never heard about that, and I'd really like to learn more about the ramp thing! If anybody has some experience with that, please do tell the details, the whys and hows and everything.
Somethign else, it's been a while, but iirc that has always worked for me unless there was a screwup somewhere... say, like no food or alcohol left and totally desperate dwarves... what I'm talking about is this:
I tend to channel some tiles inside my "courtyard" out and connect them to the river. If I have really dangerous fish on the map I add a little evaporation chamber and two floodgates, so I can get the watery tiles dry in a pinch, killing off the fish.
This is easy and quick to build, can be among the first things you do on the map, basically just so you have a "safe water source". Sure, a well would probably do better, but a well needs a chain (if you hadn't brought any) and either pressure managment or a map that doesnt freeze. either way, just a little waterfilled moat inside the walls is easier to pull off.
then I just designate the tiles around the water as water source and fishing area and set the dwarves options to "zone drinking/fishing only".
Not totally dwarfproof, sometimes they do wander about to the dangerous river, but iirc, mostly it works, doesnt it? correct me if im wrong.