Welcome to MAAST and watch your Undulated trigger, great fish just tends to be very aggressive at times. My brother in-law had one and it killed his Niger Trigger that was twice the Undulated's size. My brother in-law was so mad he quit feeding it for three months and it lived on the algae that grew in the tank until he sold it back to the fish store and what is more amazing is the Undulated got fat eating the algae.