I had 3 boys in a 10 gallon tank, divided. I got the first two, Calypso and Kwimby, in August 2010. I got the third, Suicune, in November 2010. Calypso died suddenly, in December 2011. Kwimby died after being bloated and lethargic for about 5 months in March of 2012. Now the third, Suicune, has developed a large tumor looking thing, but was eating and pooping as normal, but overnight has turned very lethargic and sickly looking, so I don't expect him to live long.
Can old age bring on these conditions? Does this seem like premature death or a pretty average span of time to have a betta?