Missing Bubble Tip

[lx5litre]

I went to work for a few days out of town and my bubble tip is missing. Is it possible he died and the fish ate him? I checked the filter and there is nothing in there, the only thing I can find is a white kind of cotton looking piece stuck on the wave maker. The only thing that I can think of is that he has shrivelled up somewhere and is dumping waste. If anyone has any ideas that would be much appreciated.
Thanks,