How many of each species do you have? Mbuna are harem breeders which means to avoid aggression issues you should have at least 3 females for every male, and with the more aggressive species you should only have 1 male of that species per tank.
I'd suggest returning/rehoming the jewel, the require a meaty diet that tends to bloat the mbuna. That and I really think you'll have some aggression issues. While both jewels and mbuna are aggressive, as they never occur together in nature they have completely different ways of displaying that aggression. By that I mean mbuna have a complex display and fighting style and most fights rarely end in death or major damage, I'm sure jewels do as well amongst themselves. But, as they are unable to understand each others body language the fights between the jewel and mbuna are more likely to end in major damage. That's the biggest problem I see with mixing Old/New World & riverine cichlids, not so much differing PH & KH or even diet (though that is a consideration), but their inablilty to communicate effectively. Sorry for the little rant, I'll get down off my soapbox now.
As for you other species, you'll want at least 5-6 of each of them (remember 1m/3+ females). With the species you've chosen so far, you're setting up a pretty aggressive tank so you'll need to stock future choices very carefully. I'm not that great with stocking larger tanks, but I'd think you could safely house 20 adults for light stocking and 30 for heavy.
If you are not wanting an aggressive set up, you'll need to return/rehome the
Melanochromis auratus (probably THE most aggressive mbuna available in the hobby), and you may consider only sticking with one
Pseudotropheus crabro (bumblebee). While I and a couple of others on here have had luck keeping them singlly, I understand they can get very aggressive in groups.
Can you post a pic of your unknown yellow fish? If not, the three species that come to mind that are yellow are:
1.
Labidochromis caeruleus, they are yellow with black stripes on their dorsal, anal, and ventral fins.
[URL="http
/www.cichlid-forum.com/profiles/species.php?id=713"]http/www.cichlid-forum.com/profiles/species.php?id=713[/URL]
2. Male
Metriaclima Lombardoi, adult males are solid yellow with faint vertical bars, juveniles and females are light blue with dark vertical bars. Another pretty aggressive species.
[URL="http/www.cichlid-forum.com/profiles/species.php?id=798"]http/www.cichlid-forum.com/profiles/species.php?id=798[/URL]
3. Female
Pseudotropheus saulosi, juveniles and females are solid yellow while adult males take on the light blue with dark vertical bar coloration.
[URL="http/www.cichlid-forum.com/profiles/species.php?id=1"]http/www.cichlid-forum.com/profiles/species.php?id=1[/URL]
If you have any other questions, feel free to ask. -Dawn
