I've been following this over on the Dendroboard, Devin. Whereas I can say with certainty that I've NEVER been there, there are streams that feed into the Rift Valley lakes that do have emmergent/marginal plants....it's almost reminds me of a estuary of sorts. Not in the same way where you would have mangrove swamps, and so forth, but there is a "zone" between "lake" and "stream"..... http://www.africaimagelibrary.com/me...-to-lake-tanga
See if that helps give you a better idea. These cichlids are algae grazers, so I'm certain what they would do to plant roots....I would assume that they would leave them alone and the plants would be fine.