Both the BKG's are doing fine, but I am not sure of the glass fish to be introduced to the same tank. My tank is of a medium size, so there is no question of being cramped, but I have heard that since the BKG's have a fairly large mouth, they may gulp up my glass fish which are as tiny as my little finger.. So shall I give it a try to put them into the same tank ? In case they gulp it up, I can pull it back from its mouth you know....