I have 4 buccochromis nototaenia,1 Red finned borleyi,4 placidachromis electra, 2 peacocks( one Walteri and one Blue Regal),1 fossochromis rostratus,2 O. lithobates (one red top and one yellow blaze Z-rocks)1 Copadachromis Mloto,2 protomelas insignis, 3 Ch. Rhoadesii,1 Moorii, and one venustus. All my fish are males. I have a 75 gal. but will be upgrading to a bigger tank when my fish start to get bigger. Some are 3 inches, 2 are 5 inches and the rest are 2 inches or so. I run 2 emperor 400's. I have 2 fake rocks with holes in the in about 3 different entrances/exits in the cave rocks. I been using only one because I'm afraid they take up to much space and take away from the fish open swimming area. So anyway I was thinking of getting 2 rocks to put in the corners but am worried about weight, and what kinds of rock. I don't want to have to add egg crates either. SO SHOULD I USE BOTH FAKE ROCKS OR JUST STICK WITH THE ONE? It pushes them up to the mid water range to swim, still leaves room to swim behind and around of coarse. Last little note I've been thinking about switching to sand, I have fine gravel now, but with the sand I don't know if I like the waste sitting on top until time to clean, and plus I've never used sand before. Well hope I didn't give to much INFO. LOL!!!!