[Iggy Newcastle]

Welcome to C-F

You stated the fish are all juveniles. Did you buy several Julies and a pair formed? Or did you start with 2?

Definitely setup the extra tank, especially if the exiled fish cannot leave the upper corner without being attacked. You could also try removing the aggressor.

 

[Iggy Newcastle]

Typically, you start out with 6+ individuals and allow a pair to form. Not all fish are 'compatible' with one another so you need to give them options. At that point, you either remove the pair to their own tank, or the extras. In larger tanks you may have more than 1 pair existing.

Your Julies certainly looked to be a couple. Pair bonds do break down. This is common especially in south and Central American cichlids, where a tank divider is often used when needed. I have limited experience with Tanganyikan fish, so I cannot confidently say if these fish would ever be compatible. Best bet would be to remove 1 until you can source a few more. After you quarantine the newcomers, add all the julies together into the 55. Let them sort it out.

Also, your fish appear to be Julidichromis Marlieri 'Gombe' which used to be considered Transcriptus. Hopefully someone more experienced chimes in on this.

 

[Iggy Newcastle]

Here's what I'm referring to-
https://www.cichlid-forum.com/profiles/ ... hp?id=1537

It's a dwarf form of Marlieri. I do have some, but no pictures to share.

 

[Iggy Newcastle]

cichlidae.com shows that Transcriptus is only native from 3 localities in Congo. Marlieri from the country Zambia. Many localities. It's confusing