Certain water types

Question
I asked a few weeks ago about my Betta, Cadmen. He had/has fin rot (possibly), but seems to be recovering well. He used to sit motionless in the back corners for abnormally long periods of time, but now swims around a lot, and wiggles his head back and forth at me when I wake up in the mornings and at various other times of day, which I've heard means he's happy.

He has no heater or filter and lives alone in a three liter tank with two fake plants. I am, however, currently saving up to buy a bigger tank and a heater.

I was wondering a few days ago if it was possibly the kind of water I use that originally gave him the Rot - I used tap water for a time, but as I live in the suburbs and my water comes from a well, and is treated in my basement via salt tablet things, I stopped, fearing it was worse than city tap water.
I was wondering if it's safer to use the water from those really big water jug things (like the kind that you put in those office water fountain thingys - the one that sits upside down to feed the water in?) The label on what I use says 'Ultra Pure; Reverse Osmosis Purified Water'. I've been using it essentially since I first discovered the fin rot, which has been a while, but I'm curious. Is it safer to use that water than that of tap?

Second question. How long can a Betta live without a heater, and generally in the described conditions? I have no job and only recently graduated from high school, and my family has been running low on money, thusly has no room to spend food money on a water heater.

I have one more question - how do I know when to stop administering the fungal medication that I use to treat his fin rot? His fins show evidence of having been growing, but still has a few clear and black flecks/strips on his fins.

As well, his... dorsal fin, I think it is (the one on his back) is limp-ish, sort of folding downwards, even when he is flaring it out. The colors on it are duller then the rest of him, and I'm wondering if this is another sign of illness, or normal, and generally nothing to worry about.


Thanks in advance - Brittaney

Answer
Brittaney,

   Tap water is always better than purified, bottled or distilled water. There are a lot of things added to those waters and most of it is sodium. I only use my tap water with a very good water conditioner that removes all the ammonia, chlorine, nitrates, nitrites and other chemicals. I would stay with your tap water, because going back and forth can be doing more harm than good.

Your Betta can live without a heater, but he won't be happy. If Betta's are treated right with a proper size home, a heater, the right food and perfect water conditions, they can live 5 years sometimes more. When we don't give them what they need, their life span is much smaller. In the conditions that yours is in now, i would say about 2 to 2 1/5 years.

Always follow the directions on the medicine bottle. With some of them, if after treatment is done and the fin rot is still present, you can do a second treatment.

His dorsal fin should always be up when he is swimming. In the small bowl you have him in, he cannot do that. Betta's can suffer from depression as well and I think that might be what yours is going through now. Even if you get him a plastic container like rubbermaid, that would be a lot better that what he is in now. All my hospital tanks are just plastic containers. They are cheaper than aquariums, and they are bigger which gives your fish more room to swim. I think that once you get him a bigger home, a heater and fix the fin rot, he will live a happy healthy life. But you need to do that as soon as you can.