If you want to grow him on put him in the 10 gallon it should be fine for now but - lots of water changes to help stop stunting and lots of high protein food like blood worm to help him grow quick - it could still take a few months though.
Its quite impossible to say if he is going to be stunted by half an inch though.....
If he is to go into your 50 gallon in your signature though, forget it you need to seriously sort your stocking out in there or get a much bigger tank. You have quite a few fish that are going to grow to over a foot (including this bichir) and deserve a bigger tank. Also mixing an Angel with a JD not sure how that will work out but it could work out. But the Electric Blue Cichlid? I am guessing this is some kind of African Cichlid - which might work with the JD but not with the Angel - Africans need specific set ups with high Ph as well as it effects their growth and development and also the long term health of things like their heart and digestion system.
For some of the fish like the Plec or Bala Shark you need a much bigger tank (this is also the case for the Leporinus, Sun Cat and possibly the African Knife and Eel. You need to be looking realistically at around 100 gallons at least for most of these species IMO.
Wills