If you are doing fish-in cycle, then you should be prepared to lose some fish. Thats just how it goes....I know from experience LOL!

For most schooling fish, especially tetras, 6 should be the bare minimum.

I am thinking that stress due to small school and to cycling is probably freaking him out a little.

Also I have notices with my small tetras that they get a lot of food by nibbling the particles of broken flakes by the other fish that drift past, but its more difficult to see him feeding. Glad you had some luck with your method in the previous post.

You could also try to encourage eating by changing the food some. once a week or so, for those kind of fish, the frozen blood worms are a very good treat. You dont want to feed them that all the time, they are too fatty, but for a starving fish, it may help boost some needed energy and appetite.