1) Totally normal, also the air pump isnt necessary if you have good surface agitation. I would get rid of it and add a powerhead for extra flow.
2) Also normal, could take a week for him to accept food. They typically wont starve themselves to death unless there is another issue. I would try a small piece of shrimp on a piece of thread or fishing line, suspend it in the middle of the tank and leave the room.
3) Up to you, could even use sand.
4) Routine is important, put the light on a timer and let the fish get used to it.
I would also start looking for a bigger tank, a 20 gal isnt going to last long.
2) Also normal, could take a week for him to accept food. They typically wont starve themselves to death unless there is another issue. I would try a small piece of shrimp on a piece of thread or fishing line, suspend it in the middle of the tank and leave the room.
3) Up to you, could even use sand.
4) Routine is important, put the light on a timer and let the fish get used to it.
I would also start looking for a bigger tank, a 20 gal isnt going to last long.