I had a 75g and i fit 8 ornate, 8 cb endli, 4 senegal, 4 albino sen, 2 delhezi, 2 gold dust, 2 palmas polli, 2 BV and 2 nigerian lap. To be honest they will be still in that 75g from march till november of 2016. I just got lucky with the 180g for $250, but i had them in the 75g for 6 months. Thats why when i transfer them in the 180g most of them were 6". If you want cb endli and ornate go for it, grow them out in the 55g, it takes time for them to be full size, im not saying do what i did but its a good example what you can do with the 55g. Like i said before its better to grow them now before you get a WC specimen since most WC are being sold 7"+. And growing them in a smaller tank you can observe them better, better than having a 2" poly in a 6' tank.