That's quite the endeavour...I believe Madagascan fish (cichlids, anyway) can be quite pricey. However, I think you should be able to put something together. Here is a start (albeit a rather dizzying one): http://www.mongabay.com/fish/data/Madagascar.htm
There are just very very very few people interested in this type of setup and/or part of the world. If I come across more I'll add it to this thread, but it's going to take some searching to really come up with good stuff. I would recommend just using a search engine and trying to find as many pics of different Madagascan waterways as you can to get a feel for the landscape there.
, not biotype.