I would divide that tank up into quarters with mesh of some type to keep them apart.
I tried to grow 12 haitiensus together at first, and all died.
Next I tried 6 older haits together, 5 out of 6 died.
After finally getting a pair, I have also tried raising their spawns together.
The only way they seem to survive is individually, either in separate compartments in the same tank, or in separate tanks until mature.
Above is my pair, it took many trials and 19 deaths to get it.