i have had my betta, Newton, for about 3 months now. he lives completely alone in his 1.5 gal hex tank. a couple of days ago while feeding him, i noticed a hole in his L side just behind his pectoral fin. it is about the size of a pencil eraser, and it seemed to have just come up overnight!! i feed him every other day, and i hadn't noticed it prior. i am very concerned about his health, even though he eats & swims around as if nothing is wrong. i really don't even know how he injured himself, becasue there isn't anything in there he could possibly get hurt on. in the tank, there are smooth round stones on the bottom, a ceramic mini sign reading "no wake", and one plastic plant. no filter, no air bubbler, and no other fish. is this an ulcer?? also, i want to know if it is safe to use a product called Melafix?, it reads on the label that it helps w/ ulcers, fin rot, etc. PS.. he has never been infected w? ick or had any previous illness before now. please help, i welcome any suggestions. i pray he won't develop dropsy 
