Harry had thought getting into the water would be simple.
Yet less than half a minute later, he burst back out, his face alternating between pale and ashen, his expression plainly showing his lingering fright.
Around his body, a Protego Totalum was already flickering violently, on the verge of collapse.
Hermione and the others were just about to ask what had happened when a great swarm of little things emerged from the water, accompanied by a teeth-grating crunching sound.
"What are... those?" Ron stared at the densely packed things on the surface, their mouths open to reveal sharp fangs. The sight nearly triggered a fear of clustered things in him.
They were small fish that looked only about three inches long, their diamond-shaped bodies mostly silver, with red bellies. Their slightly oversized heads and open mouths full of sharp teeth looked particularly unsettling.
Most unsettling of all, a considerable number of them had obvious damage to their bodies. On the worst ones, even the bones inside were clearly visible.
Yet these fish were still leaping about, and those with obvious damage looked especially lively and ferocious, jumping the highest out of the water.
Only after quite some time, seemingly realizing that they could not reach Harry and the others in the air, did they reluctantly sink back underwater.
The surface, which had looked as though it were boiling a moment before, became calm again in just a few breaths. It was mirror-smooth, giving no hint of the many ferocious little fish beneath it.
"What... were those things?" Harry asked incredulously, then looked at Hermione.
He did not know whether Hermione knew either, but turning to her at a time like this was entirely instinctive.
And once again, Hermione did not disappoint them.
"Red-bellied piranhas, also called water tigers." As expected