You probably scared it
To get to the other side! Where did you get the back and forth kind? Mine only swim to and fro. In semi-seriousness, angelfish in their natural habitat have freedom of movement and exercise that. In an aquarium, back and forth is the only way to go. If you will allow a moment of anthropomorphism, they're probably looking for the way out.
because its probably sick and need to see a vet... if this continues notify your vetit probably has some kind of diseaseMost likely a swim bladder disease
no. EDIT: Incorrect. Fishyfisher82 has a two year old veil angelfish in a 36gal tank (and all the size that implies) with a trio of glass cats who have been coexisting for well over a year. So long as the fish can swim quickly and are not too tiny, and you only have ONE angelfish, you're fine. Angelfish will most likely eat guppies, though.
For the most part you are looking at mid level for an aquarium. However they do go everywhere. My personal stocks I have seen tend to go more upper level than lower when not in the middle.
No it is not, as you can see, the queen angelfish is much more colourful. The angelfish is just black and white. Except for the male, it is colourful but not as colourful as the queen angelfish.
There are not many fish that are compatible with Angelfish. Only Angelfish are truly compatible with Angelfish.
If it seems that the fish is attempting to swim upwards your fish has a swim bladder problem. Your fish will die from this eventually. Pet stores may well attempt to sell you something to fix this. IMO you would be wasting your money. I would destroy/euthanase the fish.
The angelfish is a breed of fish.
angelfish can be eaten by squids
Angelfish live in water. They do not get it.
angelfish mate in early summer