the 220gal should be fine for quite a while.. you will know when you need to upgrade.. when they start splashing water or they bump their nose from swimming fast too fast they will need more room.. i had my two in 220gal then i ordered the 300gal when i suddenly lost them. I waited too long.. the best idea is a stock tub {pond} if you cannot afford the large tank... the nuts can be just little peanuts out of the shell.. remember they need to get bigger before you introduce chewy crunchy food..as they grow give them zuchinni, small grapes..{cut in half} piece of raw carrot, string beans.. and pellets for protein.,.. good luck with your babies..they truly become awesome pets.. so awesome you wish you could hold them in your arms... they appear so affectionate and happy..
As far as harming other fish my two pacus were alone except for one african cichlid.. they acted like they were his body quards..he would be in the middle of them waiting for his food.. they were together 6 years.. pacus will not usually eat other fish if fed well on a vegetarian diet.. with normal amount of protein.. it is the pacus who are raised to eat goldfish and other abnormal diets that have problems with aggression.. mine were platter size but they did not know it.......hehe...
