I am going to keep some south american cichldsin my 220l tank. I was planning on getting a pair of festive cichlids, maybe some rams or apistogramma and perhaps some blue acaras. Im just looking for advice on other copatible species, water parameters and would it be possible to keep a severum? Ive seen a minimum tank volume of 170l on some sites but surely this cant be big enough for a 20 cm fish?? Any help is welcome!