i've had it for over a year in a regular tap water. i dont measure parameters. it looks cool, but just so you know. it is a very lazy and nocturnal fish. it does not
do much. i have only seen it eat once (it ate my female betta). it also ate all my expensive gobies at night.
i have endlers and cherry shrimp in the tank, so i am pretty that it eats them at night as well.
it's pretty fat, so i know it's eating.
the tonguefish are a lot more active and they eat blood worms and black worms all the time. even during daylight hours