I have read certain accounts of people saying loisellei they've kept were very nippy and prone to chasing other fish and starting fights, which is exactly what I've seen with mine. The managuensis I've kept were all relatively placid. Certainly able to hold their own, but didn't go looking for fights like my loisellei do. Just my experience though, not necessarily the normMost people who have owned other parachromis will dissagree especially with RTM or freddies. One of the reasons I bought loisellie is that everything I have read and people I have have experience say that they are the least aggressive parachromis.