african Malwai tank mates

I wouldn't mix africans with oscars. Since you have an african i think you should continue with africans and add a few more species. Or if you want to go with an oscar take back the zebra.

Are there any other african mbuna spcies you like?

red devil most def. as long as the zebra is smaller then the RD it should be fine.

Buy 6-8 more juvie OB Ps Zerbras online. 8 syno multipunctatus and maybe another 6 juvies like protomelas taeniolatus or sciaenochromis fryeri. Feed a staple of spirulina and occasional frozen brine shrimp and fresh veggies.

Certainly don't mix new and old world cichlids. Reason being a vast size, water chemistry and behavior difference = endless headaches and dead or messed up fish!

That 75g has nice Malawi options like these. Enjoy the research! Don't be hasty. That big OB will be happy to wait, and dominate or not care!

Take your time. Pseudotropheus Estherae are a large bodied aufwuch Mbuna and are readily available from reputable dealers.

Re-arrange the tank rockwork when you add new fish... this will help your lone dominant zebra loose his sense of territory and the other new fish will have fair grabs at staking a territory. You could do endless mixtures with africans... just make sure to keep the group either mildly-agressive, semi-aggressive, or very-agressive. If you mix 'calm' africans with agressive africans then your bound to have deaths and/or severly stressed fish... and stressed you too!

good luck

Bumblebee said protomelas taeniolatus or sciaenochromis fryeri.
Protomelas taeniolatus are aggresive when breeding, also claim large territories. Possible best kept alone. (these are red empurors i think, can't spell it) lol
sciaenochromis fryeri, just territorial, mabey better choice for your tank.
Syno multipunctatus are excellent fish, very active an peacefull, probaly the reason bumble reccomemded them!

The take-home point from Bumblefish's post is to avoid mixing old and new world cichlids. He makes fine suggestions re: stocking, and the tank would look great as he portrays it. You can put together an infinite number of combinations starting with the big zebra. Doing research on the species first will increase your chances of introducing new fish without problems.

Some random thoughts from me:
1. Synodontis catfish generally coexist very well with african cichlids. The catfish leave the cichlids alone and vice versa.
2. Keeping multiples of a given species generally is easiest, and generally it's preferable to keep one male and a number of females.
3. Similar looking males of different species (e.g., where males of both species are orange) are likely to fight for dominance, just as if they were the same species. In fact, a male of one species will fight with any fish that looks like it. Male kennyis, for example,are yellow and will attack and eventually kill yellow labs of either gender.
4. For territorial fish, lots of rockwork and things to break up sight lines between territories will help decrease aggression.

HTH,
Jim