The fake egg dispensers that actually shoot out spikey green enemies do not fire if you have 6 eggs already. This can be a very useful technique for navigating the cave safely, as they fire randomly and can be difficult to avoid. The fish also jump mostly randomly, so pretonguing can be a helpful way to shield Yoshi from jumping fish. Just be sure to jump and release the dpad, to avoid losing speed.
The end of the level can be tricky to navigate, due to green piranhas. Check out the video for route guidance.