I'd say upgrade to a 55, do not use any plants and use lots of rocks ( enough so each fish has at least two spots to hide), add more fish ( I recommend acei's and electric yellows for beginners) and do water changes every three days or as necessary. I have a VERY overstocked 55 African tank. I started with only a few and have just kept adding more and the aggression has gone completely away. They even huddle together at night.
Best of luck, and the I.D's above are correct to my knowledge.
Best of luck, and the I.D's above are correct to my knowledge.