Clicking in my tank

[demon666]

a snail being pushed around on the glass by the powerheads(flow) it happens in my tank quite regularly........

[Myanth]

Or clumsy hermits, I get them falling off rocks against the glass. It can be pretty loud... especially if a fish throws them off. My big perc doesn't like hermits at all.

[deep6er]

I have seen my snails do a little dance number on my glass and it's shell was hitting the glass making a tap sound. yours might do it too