thats funny , but he is totally healthy . most of the time he is swimming around constantly, he is never still and thats why his mouth is open .overfeeding , water that is too warm and some diseases can also cause this . i was checking him out this morning and he does close his mouth but as soon as i get near or walk by the tank he starts swimming and his mouth is open . that's scary i lost my 2nd umbee more than 25 years ago that i got from rare and unusual cichlids (shannon forest) . that fish was a bad ass , real pretty but one day his jaw got swollen and stuck and he died in about 5 days and that really sucked ......