Just Between Us Girls, Eh...
Hi,
As Hallen and Tug say, the problem
could be the fish, based on your description of the fish and the source of the fish, I am going to say it is likely
water parameters; these are
difficult, sensitive
fish. :gw
For whatever reasons pH swings within 1.0-degree from CO2 injection
seem to have little effect on the critters, whereas some of the more sensitive critters can be harmed by a 0.2-degree pH shift via salts.
I do not pretend to understand it.
I would advise that your base pH be
below 7.0, I would also anticipate roughly a full degree drop because of CO2 injection. The idea is to keep the base (pre CO2) pH level acidic and stable.
Alkalinity is,
I think the major player
many folks keeping Papiliochromis spp. strive for near zero
(as in, nada, nothing, zip-zero, uh-uh, 0.0) dKH. Being the scared of pH crashes and such-like kind of evil plant monster am not comfortable with that; I maintain a little under 2dKH, though I have never seen any non-breeding problems up to 4dKH.

I concede that breeding and certain disease resistance does appear to be better at lower alkalinity than I use. (Jonny and Philosophos would be amazed at such a concession on my part, so let us keep this between us.

)
General hardness does not seem to be critical, I recommend keeping it in the 4-6 range, but I doubt upward of 8 or even 9dGH would be harmful.
I do not think that excessive current is a problem with these guys as long as they are healthy in fact I rather think they enjoy a good current.
I cannot overstate the importance of caves and hiding places, get something in now!
They are not shy; they certainly know who feeds them and are greedy little buggers. They get along well with other mild mannered critters, most un-cichlid like.
Live food is a very good idea, especially when breeding.
Biollante