Small fish, lots of small fish. About 30 years ago we started a club, Ultra Light Hawaii. We only use 1#, 2# and 4# test line. The reefs around Oahu are pretty fished out, so chances of catching anything of any size (2 pounds or larger) is pretty slim. But using ultra-light you catch a lot more fish than if your using 15 or 20 pound test.
Now days when I use the Tenkara rods... I only use up to 5# test tippit, so I don't even worry about catching large fish. All the 3 pound or larger peacock bass just keep breaking my line.