It's hard to say......I couldn't really see the injury in the video. They are pretty active though and it looks like one is being harassed....is that the one with the injury? It may have bumped into something. Can you get a better photo of the actual injury? It may heal on its own with clean water, maybe add some STress Coat to promote healing. If it looks infected then it may need to be treated with meds.
I also looked at your profile....not sure if it's accurate but if so the sharks will need to be upgraded or rehomed; they do better in groups of 5 but they can grow up to 3 feet. The CAE can become aggressive as it matures and they grow large (10"+) as well.
If it seems like one barb is bullying the others you can try putting it into a breeder net for a few days for a time-out. Adding more to the group might help mitigate aggression as well. The giant danios would do better in a larger group too, although you'd probably need to rehome the sharks and CAE before you can add anything else depending on how large they are now.