Can i add this fish in this tank?

I would get 4 otocinclus(they do better in schools) and instead of neons, get glow light tetras.The neons and cardinals look so similar I would just stick with the cardinals myself,they are the better looking of the 2,and are usually healthier,IMO.Adding one more school of such small fish will not be a problem in that size tank.But I would not add anymore.