The Black ghost knife fish (Apteronotus albifrons) has never been bred in captivity. They are known to be egg layers so they can not get pregnant. Growing very large, over 18 inches and comming from fast flowing tropical waters (about 75F) they are not easy to keep and not recommended for beginners. They also have an electical ability so may give a handler a mild electric shock. My advice is for you to look for something else to keep until you have considerable experience and are successful at keeping other easier species tropical fish.
It looks like it normally does except has a slightly larger stomach.
A pregnant ghost fish.
Black moors are a variety of goldfish which are egg layers so they can't get pregnant.
black ghost knife fish gets nutrients and energy from the food it eat
No.
The maximum length of the black ghost knifefish is 40 centimetres
they can be 49cm.
No.
Yes it can
Black Ghost Knife Fish are semi-agressive. They should be fine though. The angelfish should be fine.
fish about 5in or 4in lowest
Yes if its the only one?
Depends what store!
Your fish can not be pregnant so don't panic. They are egg layers so their eggs are fertilised and the young hatch out in the water not in the fish. Black Ghost Knife Fish (Apteronotus albifrons) grow to over 20 inches long and need a very large aquarium (at least 6ftx2ftx2ft) and are extremely hard to breed so the chances of you manageing it with your lack of knowledge (of the species) are very unlikely.