I keep my senegals with congo tetras and pearl Gourami , and so far no problems.
If you don't mind me asking what price are the Delhezi going for, as I am thinking of getting some?
And what pet shop is it that you work, I might have talked to you at some point unknowingly.
And if you are ever wondering what species are allowed in the country This is the link
the tetras and gouramis will be picked off one by one.