at present I have a female krebnesis pelvicachromis pulcher it has been in my community tank for years now. At the same time I bought a male and female pelvicachromis moliwe they were in a different tank within a month the male died so I replaced it with another male the female then died about 2 weeks after replacing male and then the male about 2 weeks later water parameters were fine I know the water in my area is hard and was wondering if that had anything to do with it although my other female krib is fine in the other tank.Any ideas as I would like to try them again.