The tank started off like a regular 75 gallon, 4 foot from side to side, 18" front to back. But it is unusual in that has a 30 gallon sump which hold about 20 gallons of water. The sump has 3 liters of Seachem Matrix (and I can easily go to 4) and a 1000gph pump, which is not even close to pushing 1,000 once it goes through all my plumbing.. So it has far more water than a usual 75 and probably far more filtration.
I also have a Universal Rocks 3D background which I had them cut for me to just cover the internal overflow in the tank. This takes up significant space where the overflow is, there is only 9" front to back for about 7-8 inches of length. (This might actually be an advantage, since it does break sight lines across the length of the tank.) The rest of the background only takes up 1 to 4" depending on what part of the background you are looking at it. The rocks are all Universal also. I think there are enough nooks and crannies but frankly I'm worried that some of the crevices are too small. I also might not have enough open sand space for digging. The substrate is eco-complete cichlid and I have 11 pounds of dead sea "rock" in the sump for buffering. I've not yet had a chance to measure the water parameters.
A picture is worth a thousand words so here it is, just filled it.
(hmmm, that's odd, in Preview the picture is only showing the left 3/4ths of the tank!)
So, it can probably hold more fish than a 75 because it has more water and filtration, but it can probably hold less fish than a normal 75 because the interior space is a bit limited.
I'm not a beginning fishkeeper but this is my first east african tank. I know I want Mbuna, both because they are smaller and because the girls are dull.
I'm leaning heavily towards the Pseudotropheus saulosi. I can probably get them locally and some of the online houses stock them. (I only want tank raised, I've read about the decimation of the natural population.) What attracts me to them is the sexual dimorphism they display. Other fish that do this could also be candidates but frankly, if I keep Pseudotropheus saulosi I know I'll have buyers in the area for them.
I think the tank needs to be a single species tank because of the space limitations but that's just a guess, I've not kept Mbuna before. I've also considered Pseudotropheus demasoni and Labidochromis caeruleus. The advantage of this pairing is that I can easily balance the yellow and blues. The disadvantage is that I'm probably not ready for the aggression of the demasoni.
My desire for the tank is a good mixture of blue and yellow, it can be heavy on the yellow, but I would want 4 (or more!) blue fish. This could disqualify the saulosi. I also want interesting behavior, but I gather that that comes for free with Mbuna. (I have another 75 gallon tank with gorgeous fish that for the most part just don't move except when it that time of day to spawn..., boring except for the sex time, which at least they do pretty much for a few hours every day.) I also wouldn't mind a fish where there was a market for the fry and that means I want to completely avoid any chance of hybridization.
I'd appreciate any advice you all can give.