Check your water quality for ammonia, nitrite, nitrate and pH.
Do a 75% water change and gravel clean the substrate every day for a couple of weeks.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.
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Make sure the tank has a picture on the back.
Have some floating plants in the tank.
Increase aeration/ surface turbulence.
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Stress from tank lights coming on when the room is dark can be an issue. Fish don't have eyelids and don't tolerate going from complete dark to bright light (or vice versa) instantly.
In the morning open the curtains or turn the room light on at least 30 minutes (or more) before turning the tank light on. This will reduce the stress on the fish and they won't go from a dark tank to a bright tank instantly.
At night turn the room light on and then turn the tank light off. Wait at least 30 minutes (or more) before turning the room light out. This allows the fish to settle down for the night instead of going from a brightly lit tank to complete darkness instantly.
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Have a small television on in the room when you are out. You don't need the sound but the flashing lights can help the fish get use to movement in the room.
Tie some plastic streamers or ribbon to the front of a fan and have it on low and oscillating. The movement of the ribbons will help the fish get use to movement in the room.
You can have a mobile in the room and the fan will blow that too.
