Siamese Fighter Tank Size

Hi all,

Need a bit of advice here.
I have a male Siamese Fighter Fish in an aquarium the size of 19cm by
19cm by 8cm with no filter. I change the water manually by removing a
quantity of water and replacing new water and then adding a drop of
anti-chlore. Truthfully I cant afford anything else and wanted a
portable aquarium that I can place on my desk when I study.

As far as I know the facts of the Siamese Fish a
1) they dont like circulating water as they go up to the surface to
breath and therefore do not need flowing water to run over their
gills. Flowing water actually tires them out as they have to stabilize
themselves.
2) They do not need large tanks as they tend to be territorial.
3) They can mistaken other fish for fighters and then attack them. Ive
read a number of posts about Fighters attacking other fish.
4) They are not big eaters and a lot of them get killed by overfeeding

These are the facts that Ive received by reading posts and websites.

Therefore my question is is my current tank situation ok? I know its
not the best but naturally the best costs a hell of a lot more then I
can afford. I just want to know that Im not causing harm t the fish in
any way.

Thanks,
Doug