important question about oscars and clown loaches???

I've heard it stresses the fish not to have any gravel

I have 1 oscar and 6 clown loaches. They are in seperate tanks however. Both tanks have sand for substrate. The oscar is doing well. Besides having a gut. The clowns are also doing well. I've had them in there for months.

Every tank I set up now has sand in it. If it's going to have substrate in the bottom it always gets sand. I like the natural look. Most if not all fish come from places with sand bottoms. Somtimes nasty mud bottoms.

I don't know if it's easier to clean... But. The things needed to be cleaned (like food and what not) is usually sitting on top of the sand and the catfish usually clean that up. I hardly ever clean the bottoms in my sand tank. I'm not suggesting this cause I could have been doing something wrong all these years. However I've never had any problems.

As for bare bottom tanks... I only keep bare tanks for feeder fish and guppy fry. I tried it with bigger guppies but they seemed stressed by it. I decorated thier tank to ease that.

only problem id see with the oscar and no substrate is hell be attacking his reflection all day, and a common thing, (with arowanas anyway) is they will tend to always be looking at the bottom to see/fight the refelection and it may cause drop eye. But i havent seen it happen and i think its just a matter of personal preference on what you keep or dont keep on the bottom of the tank.