I grew up fishing 120, both Catfish pond (west pond) and Grenadier. Every spare weekend I'd be down there, might not be the best fishing in the world, but I love the place.
Grenadier produces decent largemouth and the odd pike. You've got to be willing to walk the banks and cast to cover. It's not fast action, but the bass are in there. Spinner baits are pretty good. Tons of action for little kids and panfish junkies though: white and yellow perch, bullheads, bluegills, pumpkinseed and crappies. The dock on the east side of the pond gets way to much fishing pressure, so wander around and find a nice shady spot under a big ole tree, throw on a worm and have some fun. There are some very big carp in grenadier. Corn is killer, go the day before, chum a couple spots around the time you plan to fish. There should be some fish cruisin around when you come back to fish the next day.
Catfish (west pond) has carp, bullheads and sunfish. I've only ever caught bullheads and sunfish though, but have seen some big carp cruisin' around. If you can access it from the swansea ravine (below swansea public school) it's more scenic for sure. The fishing is ok off of Ellis ave. though.
Also 119 is the humber bay park. The man made ponds are full of carp. There's also largemouth in them, but they aren't too big. You can cast from the lake side break water for salmon and trout in the fall. The mouth of Mimico creek is right there as well so there's a good sucker run in the spring. The available species are pretty similar to Toronto Islands. Apparently there are pike, but i've never caught or seen one caught. The go to species in the ponds are definitely carp, they're pretty easy to catch if you're set up for them. Humber bay pond is right on the martin goodman trail, so it's easily accessible by bike from downtown. You can take the Queen streetcar or the go train to Mimico.