You must be new to this section. i breed monos in a 120 and been a part of this site for a very long time. Probably been keeping peacock bass since 2009. You asked a question and i gave you my honest answer. And to correct myself i meant either 2 of mono or 2 kelberis can be kept in a 120 with proper care.as monos can get 24--30 inches, and kelberi can get to 187+ inches, and no you can put 4 or 2 of them in a 4X2X2 they will actual GROW to the size of the tant