I agree, the labyrinth organ is a back-up system in case Oxygen is short in the water. Even if the fish isn't consciously using its gills, and is relying on its labyrinth, the ammonia laden water would still come into contact with some parts of its gills. Gill covers protect them for the most part, but if they worked perfectly then fish would never get parasitic worms in their gills and what not.
:OT:
gingerinaustin, what a beautiful fish you have!!
:OT:
gingerinaustin, what a beautiful fish you have!!