One of the advantages of having 20 longs with the short end out is that you can pack a lot of tanks in a small space. One disadvantage, especially if there is only ambient lighting in the room, is that you can't really see what's going on in the back of the tank.
I've been growing out some...
...so I got a pair of these guys from Julie (thanks to Tony for bringing them back for me!)...
Mine are a lot smaller than this but you get the idea:
http://www.cichlidae.com/gallery/species.php?s=1214
I dropped them in a divided 2'x2'x1' tank with some PVC pieces, a little sand and a couple...