After you grow it up I am assuming. As a baby I would start small. But ultimately I would aim for a 75. I am about to set mine in one and it is just over a year old.....bought as a 3-4 inch tiny baby and now over a foot.
at least 8ft. dia pond and 2 1/2 or 3 ft. deep would be ok, but 4 is better! So probably 750-1500 gal pond would be ok, so long as the dimensions are good. As for aquarium for limas, I would say to house them for life 125 is the bare minimum. everyone seems to think they can only get to 18 inches, but there is some people that have them over 20" and in the wild they regularly get over 24" and the record was 33". So there you have it!