Oscar are to big ,add a betta fighting fish. Veil tail or other type but try getting a veil tail or halfmoon cause their tails will cause them to be slow and not catch The tetras at all .they will see it as a threat and will always be on the defense (schooling)
Sent from my iPhone using MonsterAquariaNetwork app
The easiest answer is that you do not have schooling fish. Most of the phantom tetras will only school very loosely, if at all.
A medium-large ornate bichir significantly improves schooling behavior.
It does cost you $2-5 in replacement fish nightly though.
Schooling is for fighting only. Once the threat is over, tetras and barbs just sit and lounge.