Yep, they would do it and it made the Discus mad. Saw the Discus
respond many times grabbing them afterwards in their mouths until
finally the growns ones ate them all...... Was kind of funny at first.
The little ottos like to move around the tank once in a while and
sometimes come to rest on the Discus. I will probably not own any more
CAEs, but may rent one from time to time. I have noticed on a new
tank.....Diatoms grow like crazy.......after a while no more. I have
always imagined it had something to do with the new glass.......

Silica, or Silicates, cause diatom algae, so new glass, would seem to have a
thin film
of silica on it, or until some other film is established... so you very well
may be perfectly
correct on your corelation....

The pH is crashed in all but my guppy tank....its a wonder none of my
fish have died the last few years.... My last otto was in my guppy
tank....

....bummer....