It is normal for a goldfish to occasionally swim around the top of the tank. If they are spending an elongated amount of time up there than there is usually a problem with your water quality. The most likely cause is not having enough dissolved oxygen in the tank's water- you can easily fix this by adding an aerator to the tank. Run some water quality test- if anything is not within normal limits do some large 50-75% water changes until they return to normal.
I don't know if it is normal or not, but my sister had goldfish that would jump out of their tank when she would walk into the room. She would have to scoop them up and put them back in.
Goldfish may hang out at the top of the tank because they are trying to get more oxygen from the surface of the water. This behavior can indicate that the water in the tank may not have enough oxygen for them to breathe comfortably.
It is normal most every goldfish does it, don't worry.
Your goldfish may be making bubbles in its tank because it is trying to breathe air from the surface of the water. This behavior is normal for goldfish and helps them get oxygen when the water is low in oxygen levels.
leave a gap
A goldfish can live in an opaque glass tank as long as you keep up with necessary water changes. Like a small outside garden pond goldfish are only viewed from the top.
To prevent your goldfish from making bubbles at the top of the tank, ensure proper water quality by regularly cleaning the tank and maintaining appropriate water parameters. Additionally, provide adequate aeration and surface agitation to prevent bubbles from forming.
Provided that you do not have a singletail goldfish in your tank as they are faster more aggressive swimmers. Also make sure you check all your tank decorations to ensure that the fish cannot harm themselves on anything sharp or pointy.
Because it is there instinct ! haha
It's most likely already dead.
Yes
It is important to remember to put things in a goldfish tank, even goldfish get bored. Some of my suggestions for tank decor are artificial plants and a "hidey hole" for your goldfish.