My girlfriend's family got a small fish bowl and a betta, maybe a few months ago. They have colored marble things as substrate, and a type of decorative cave. For the past few weeks, it's been in the cave, not eating. The bowl has no filter or heater. Worrying about the betta's health, I tested the temp, which was something like 66F. I know practically nothing about FW tanks other than they need a temp of around 78F, and that the betta should be in a 5G+ tank (which it isn't). I told her mother that the fish would greatly benefit from having a heater. I also told her if she couldn't find a small one that would fit in the bowl, that she could borrow mine, but would need a bigger tank, since the heater wouldn't fit. It's symptoms are: Pale Less active Loss of appetite They also said that it's stomach was swollen, but I wasn't able to check that out, since it's dark where he hides. Does a nitrogen cycle happen in a tank that small? They do 100% water changes, which doesn't sound too good to me. They use water conditioner to remove the chlorine, though. What can be done to help the lil' guy?