Ive raised a male in a 75g,he was 2"when i got him!!by the time i gave him away,a year after he was 4".a freind now breeds him,oh yeah i currently have 16 in a 125g had them since june this year there where fry when i got them,so small i thought i had only 15!!!!Know there an inch to two,the eat twice a day biweekly water changes 50%,n ive seen faster growind severums,not including keyholes,pbass,jaguar......Yes fastaes are one of the slowest growing cichlids in my experience!!!for now i guess the 10gwill do,but i would put them in something larger then that asap!!!