Lupin;2009969; said:That is how they communicate. They make clicking sounds during feedign frenzy and skirmishes. If you notice the bifid spines found under each eye, you will see what I mean.Several of my loaches here do that when they peck each other. Tiger loaches have the loudest clicking sounds so far in my experience.
Wait till you hear 11 inch clowns click.

, and this is the only time I notice it.