Yep, your fish will probably be a bit stressed in that. You could put a decoration cave from a pet store, or use a mug or cup as a cave for him to hide in. Terra cotta pots work too, but you have to find a safe way to plug up the drain hole on the bottom so your fish won't get hurt.
its half a gallon, and i wish it was filtered and heated i have bought tanks labeled as having an under gravel filter, only to open the box and see that it's just an aeration system that sends all the dirt to the bottom, and doesn't clean the water at all. i would buy a real filter, but they cost like $40, not to mention the tank itself and the decor!
thanks for your help, and i will put a plant in, or put him in something else.
... Personally, I'd return it from where you got it (it was probably overpriced) and get at least a 2.5 gallon tank. If you're short on money, you can use sterlite bins from walmart or target (they're like 2 dollars), or a medium sized Kritter Keeper.
Believe me, your fish won't be happy in there. I can attest to that fact because until recently, I had my betta (my avatar) in a unheated unfiltered 1/2 gallon tank, and compared to now in his 10 gallon tank, he was basically a lifeless lump.
Petco is having a gallon per dollar sale, so a 5 gallon would be five dollars, a ten gallon 10 dollars, etc. :) I know PetSupplies Plus has slightly cheaper heaters and filters.
Walmart has 5 gallon kits (5 gallon tank plus hood plus filter) for 20-30 dollars, and sells really cheap heaters (I heard the heaters aren't that great, but should be alright until you can afford something better)
If you decide not to do any of those cheaper options, you'll have to still buy or make some sort of hidey cave or buy a fake (silk) plant or live one, and have to do once daily 100% water changes, preferably twice daily. :)
I agree, that tank is overpriced for what it is. You should return it and get a tank that is at least 2.5 gallons, preferably larger, and an adjustable heater. Heaters are no optional for keeping a healthy betta, and adjustable ones cost a little more but are much more dependable than pre-sets or heater pads. Keep in mind that this betta may be in your life for the next 3-7 years if you take proper care of him. In a half gallon tank, you would need to change 100% of the water and clean every day or at least every other day in order to keep harmful ammonia from building up and killing him. Larger tanks can undergo something called the nitrogen cycle (which you should definitely research) which greatly reduces the amount of maintenance. Yes, the larger the tank, the lower the maintenance. :)
Even if the water is pristine, a half gallon tank is too small to be heated, and it does not provide enough room for the fish to exercise, or provide any environmental enrichment. If you want to get him a larger container temporarily until you have the money for a larger tank, I suggest returning the half gallon and getting a 5 gallon rubbermaid/sterilite plastic storage bin from target or walmart. These can be safely heated and provide your fish with more space. They are easy to clean, and very durable, they are also useful as quarantine and hospital tanks. The major plus is that they are only about $3 a piece. You can't beat that.