Water Level

Its not unusual for my water to drop to an inch below the trim due to evaporation during the summer months. I do weekly 50% water changes, but I also dont have tops on my tanks.
 
It is not uncommon for some Arowana keepers to keep their water level a few inches below the top of the tank. It's to help prevent the fish from escaping in case if they jump.

Some breeders or sellers also do this for young aros. Instead of putting them in a smaller tank to grow out, they put the baby directly in the large tank so they wont have to move it to a larger tank in the future and possibly damage the fish. They will keep the water level 4-6 inches below the top of their tank and gradually increase the water level as the fish grows. If you're wondering why they do this, its so that they can properly feed the baby. Imagine a 1-3 inch baby aro in a 180-300gal tank.

They could easily be raised in tanks without lowering the water level though so basically, its all preference.
 
I keep mine as close to the top as I can.I don't like the water line and all my tanks have some sort of hob filter for back up and it helps keep the water flow noise down.
 
yeah, i fill all the way to the top so myspray bar is submerged, otherwise its noisy and it drives me crazy
 
In looking through ads for tanks and equipment, I see many tank pictures where the water level is 1" or even more below the trim line of the tank.
I see the same and it makes me crazy. i'm a bit ocd about the water level. I keep mine at least just high enough that you can't see the water line by looking at the tank from the front. I had a gold fish tank when i was a teen. i didn't keep up with the water level. We had hard water and the calcium build up on the glass where the water had evaporated ruined the glass. I don't have hard wtaer now, but I guess that experience just stuck with me.
Besides, I think it takes away from the appearance of the tank when the water level is visible.
 
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