Hay you could try breeding wild angels like Manacapuru or even Altum. then you'd make serious cash- one guy I know of ( hes on another forum) is going to get $10 grand- yes that's ten thousand dollars! per spawn of wild Altum!
'(sense you get about 3 spawns a year if you count growing out to selling time) thats an extra $30.000 a year.
Whats your ph?
Domestic angels on the other hand are not very valueable market wise you might get store credit from that store you got yours from but i wouldn't expect anything else.
This is why I only have 1 single angel- marbelloh. i dont want to deal with the hassle of fish raising.