How long can BTAs hide?

[JCrowe86]

I have or probably should say had at this point, a BTA that went missing. Admittedly I shouldn't have purchased it as the tank was only 3 months old at the time. It was open for a few days and then started to close up until one day it was just gone. It's been about a month and it hasn't showed back up. Yet no signs that it got chewed up by a power head either. Do they just melt away if they die? Its not possible that it's just been hiding this long is it?

 

[Mykesocalreef]

I lost one once and was gone for at least a month. Found it in my overflow extremely pale but nursed it back to health.