I notice when i walk to my frog tank each morning, that typically one or two frogs 'startle' and they jump into the water, swim to the bottom and try to hide for a minute or two.

All the rest just sit there like they were. I can even reach in and touch some of them. Most will jump away, but the ones that swim to the bottom of the tank? only one or two.

I can run up to the tank shrieking and waving trying to startle them. Only one or two.

I can sneak up on them with great stealth. Still, one or two sees me.

So, it's not quite a startle behavior, as my attempts to startle them to make them all dive down does NOT work.

It's more like a 'dream' state whereby if the frog is awakened from this state in any way, it FREAKS OUT.

i dunno, maybe i read too much into the behavior of my tank.