I see this Severum is housed with Mbuna. Do they nip at him? Probably best to keep this guy/girl in a CA/SA tank, or remove the Mbuna. I've seen some other pictures of your set up. Although you've got some really nice fish, the mix isn't appropriate in regards to aggression, compatibility, etc. That Salvini of yours will eventually start shredding it's tankmates. Just a thought to consider.