I highly doubt its an actual hystrix if its only 85, its probably a orbignyi or retic under the name of hystrix. Brazilian hystrix run probably closer to 175+
I grew out a small group of WC true hystrix in a 4x2' foot print which was only ever going to be a grow out tank, after a year it soon got a little crowded and they were moved into a 7'x30" foot print.