I just saw a video on Facebook. It showed an alternative way to clean a fish without cutting the abdomen open.
The man demonstrating this is from Brazil. He uses 4+ bamboo skewers. Puts them in through the mouth on either side of the cavity. Spins them around, holds them together and pulls everything out.
Most of the guts come out at one time if done correctly. Ingenious. I wonder how much practice it took to get the skill down.
Here the video link.