Hate to say it but are way overstocked.
Lake Malawi cichlids do not do well with other species such as the tetra and barbs. Also you are mixing mbuna and peacocks which is not a good idea either. Peacocks are very sedate compared to the more active mbuna, the mbuna will stress them out, causing them potential health issues and not allowing them to fully color up.
Can you post a clearer picture of your tank?, as looking at the picture in your profile I suspect one of the assorted cichlids is a Venustus which when adult is totally unsuitable for your tank, they get too big at 10".
I also suspect that the Oxygen content in the water may perhaps be low. Bubblers do not really serve a purpose in Oxygen exchange, the break of the surface of the water from the filter will do this.
There is also a possibility of aggression, fish will sometimes do what you describe if being bullied, it is a way of staying away from their aggressor. Much aggression in tanks is un-noticed by us but can have a detrimental effect on fish health.
To make this tank successful, could you provide some clearer pictures, so we can identify the other assorted fish and make suggestions as to how to correctly stock it.
BE WARNED though, some fish are going to have to go as you are way overstocked for a corner tank. Sorry to say