He hasn't gotten better.

[ptps]

Edit: Your fish really needs a heater. Badly. It's been repeated by several members who have been trying to help you. Is there a reason why you can't or won't get the heater despite the numerous advice given on this?

Edit again: If finding a heater to fit in your tank is a problem, or you can't find small enough heaters that will stay constant, you could always try using a desk lamp above the tank to warm the water. It's not a recommended method especially since it's difficult to control the temperature and there have been cases where leaving a light on for too long might overheat the water, but your fish isn't going to survive very long at the cold temperature you've been keeping him in either.

[ZaydeeKaine]

He has a heater; I only have a 1-gallon tank so the only heater that fits can only make the temperature anywhere between 5-10 degrees warmer than the temperature in my room. I've looked for other ones that are small enough to fit the tank and I can't find any, so he has a heater.

[SamJustice]

There are heaters for tanks that small that are strong enough to heat it. trust me. I have a heater in my tank that's supposed to heat 1-5 gal tanks. I had it in my original one gallon tank just fine.
I got it from petsmart for less than 15. Can't remember the exact price.
Completely submersible and sticks to the side of the tank so you can turn it sideways if you have to.

[ZaydeeKaine]

Can you recommend a heater? Because I've been to Petsmart, Petco and Pet Kingdom (a local store) and I couldn't find any that were small enough in size to fit the tank.

[SamJustice]

How big is your tank? The one i use in my 3 gal fits just fine in my one gal.
And that crap about them melting acrylic tanks? HA. So long as you dont have them up all the way and pressed against it side it'll be fine. The suction cups the come with keep it far enough from the side to allow water flow behind it.
I have the top fin ones in both of my 3 gal and being completely submersible, they allow you to turn them side ways or diagonally to fit in the tank.

If nothing else, get another of the heater you have now, and put them on opposite ends of the tank with a filter. (Which a filter will help with water temp, too, because it allows the water to circulate, getting warmer throughout. I'd recommend the Whisper interior for 1 gallons, worked great in mine. they even have a piece you can put on it so it's completely submersible too.)

[ZaydeeKaine]

I have a 1 gallon tank (Yes I've already been lecture that I should get a bigger tank but that requires getting a new table and a new lamp which isn't cheap). I haven't heard anything about the whole "melting acrylic tanks" thing but I can't find a heater that actually physically will fit in my tank without sticking out the top. But maybe I should get 2 of the heaters I have instead of just 1, that might help.