the angel will be fine in there for a few weeks. but it should ultimately go to the 55.
what are the water parameters)ammonia,nitrite , nitrate)?
what is the temp.?
feed flake and mix with bloodworms occassionally.
angels properly cared for will live 8-10 years.
the angel appears to have some mild fin damage.keep the water very clean ti help the fins heal.
it also looks like it may need to be fattened up a bit.
even tho they have a relatively thin profile..they will get relatively thick.
Looks like a black angel to me, I do not think it is a true DD black though, could be a black crossed with a silver, hard to tell from the pic's. I agree with star_rider, fish appears to have fin damage and also seems relatively thin. Keep the tank water clean with water changes and feed a varied diet to fatten him up.