C. furcifer do best in a tank with at least a 6' length. If you had them in a four foot tank, they would be best as your only residents.
The Gombe julis are little psychoes in temperment. I woudl go with another small variant like the dickfeldi or the ornatus or any of the transcriptus that aren't from Gombe.
Your Callochromis may still compete with your furcifer for space even in a larger tank if both are sand dwellers.
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