tbh the salvin looks like a keeper looks to be very calm and and after reading up males are larger 6 " max , id say he is about 5" , its the mayen im not sure about he is not been aggressive but all the fish seem to be a bit scared and keep away from it , it reminds me of my archer fish i used to have with its strips as it swims around like he owns the tank, its only about 3.5" its had a nips took out of his tail before i got him ,