i had a pair of dwarf frogs. they were doing fine with the other fish and the amount of salt in the water. until recently. i noticed first that the one frog wasnt eating his shedding skin. as far as i know they are supposed to eat it as it comes off and if there is a lot of dead skin, there could be a problem. then he had what just looked like a fat full belly (much like normal just after feeding). the belly never receeded.... then he began to float. he couldnt keep himself down on the bottom! eventually he died. 2 days later my other frog is showing strong symptoms like the first frog. i pulled his butt out of the water, put him in a seperate tank with fresh spring water, no salt and added a touch of malachite green, hoping to kill any parasites.. anyone have suggestions on what is causing this or what to do?