Let the man keep the cichla temensis! You have at least a year probably more keeping them in that 150! As long as you don't pack it with other fish....
Temensis will not get to 30 in the aquarium.... low 20's are more reasonable. The more you feed the more they grow, so if you want to keep them longer feed them every other day when young and I'd recommend small fathead minnows and roseys. Then when they are around 5-6 inches you can get them off live and vary their diet. I feed mine twice a week to keep them smaller and so I don't break the bank! lol I would still keep the minnows as a staple though. Market shrimp are a good cheap substitute....
Smaller fish still get great coloring... my biggest orino is only 12" and it is better looking than most, it is a year and a half old.... Just growing them big doesn't make them look better!
Have fun with them! I bet you can't keep just two!