how to cool my water?

i'd get just a regular cheap-o small hardware fan, one of those little ones with the clip at the end for mounting it in weird places. then, since you have no lid, you could adjust it so it blows air at the surface of the water. this will not only cool the water about 6 degrees F, but will aid in aeration. If you don't plan on getting a lid anytime soon, this could be a permanent solution.
 
I used to do frequent water changes over a couple of hours, lowering the temp a little bit with each change (with my 3 gallon). Eventuelly I broke down the 3 gallon as I couldn't keep the temp down, not even with floating ice bags (bottle didn't fit in the 3 gallon)! I will set it up again in the late fall.
 
For my 2.5 gallon tank, I take off the hood and put a sheet of plastic mesh over the top to cool it off (this tank is under kitchen cabinets, so I can't fit a fan there). If the temp is still too high, I put some of those plastic reusable ice cube things in the tank. I freeze them, then drop 1 or 2 in the tank. My betta usually nips at them for a few seconds, then leaves them alone. They are small enough that they don't take up a lot of surface area, and don't displace water. They do thaw fairly quickly, but it's the best alternative that I've found so far.
 
For my 2.5 gallon tank, I take off the hood and put a sheet of plastic mesh over the top to cool it off (this tank is under kitchen cabinets, so I can't fit a fan there). If the temp is still too high, I put some of those plastic reusable ice cube things in the tank. I freeze them, then drop 1 or 2 in the tank. My betta usually nips at them for a few seconds, then leaves them alone. They are small enough that they don't take up a lot of surface area, and don't displace water. They do thaw fairly quickly, but it's the best alternative that I've found so far.

isnt those resuable ice cubes poisonous to the fishes?
 
If they are not leaking they should be fine. These are the reusable ice cubes that people put in drinks right? If they are approved for human use they should be perfectly fine for the fish.
 
If they are not leaking they should be fine. These are the reusable ice cubes that people put in drinks right? If they are approved for human use they should be perfectly fine for the fish.

Yes, they're made for people, so they should be fine in the tank. I always check them to make sure they're not leaking. So far no problems. In a tank this small, you can't use the frozen bottle method.
 
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