I kept my aeneus corydoras (bronze corys) with my goldfish for a few months (my tank was kept around 70-71f). They seemed to get a long alright, the only problem I experienced was getting them food. Just make sure the biggest goldfish can't fit the corydoras in it's mouth, I've read that can be a major problem since they have spines. I usually keep salt with my goldfish as well, but removed it for corys.