No, one male and one female should not be kept together.
Chances are they'll kill each other.
What is your current stocking in there? If they're compatible you may be able to put one male in
I have a Betta with my fish at the moment ad there have been no problems yet so should they be compatible or do I just have a wimpy fighter
I curently have; 3xJava loach (Pangio oblonga) 6xNeon tetra(Paracheirodon innesi) 3xClown Loach (Chromobotia macracanthus) 4xgGuppy (Poecilia reticulata) 3xMarbled hatchetfish (Carnegiella strigata) 1xMale Siamese fighting fish(Betta splendens)1xCommon Pleco
You have all that in a 36 Litre!

you shouldn't be getting more, you should be getting rid of some you have, sorry to be the bearer of bad news
the pleco needs a minimum of a 4ftx2ftx2ft tank as they grow to 18"+
Clown loaches are the same and prefer to be in large groups
the neons guppies and hatchets are active fish so personally i'd say 2ft long minimum
Java loach again a very active fish and ideally needs large groups of 6+
Personally out of all your stock the only thing suitable for your 36l tank is the betta
No, one male and one female should not be kept together.
Chances are they'll kill each other.
What is your current stocking in there? If they're compatible you may be able to put one male in
I have a Betta with my fish at the moment ad there have been no problems yet so should they be compatible or do I just have a wimpy fighter
I curently have; 3xJava loach (Pangio oblonga) 6xNeon tetra(Paracheirodon innesi) 3xClown Loach (Chromobotia macracanthus) 4xgGuppy (Poecilia reticulata) 3xMarbled hatchetfish (Carnegiella strigata) 1xMale Siamese fighting fish(Betta splendens)1xCommon Pleco
Hi just wondering if you have room for any more fish- may be a bit overcrowded if you want to add another betta. If you think you have room for one more you can try a female. I have a 70 ltr tank with 5 guppies, 8 platties, 2 bronze catfish and a male and female VT betta. If you have the patients to observe you will know for sure if the male will get along with a female. Some males are just downright nasty and some like mine are very gentle natured and doesn't bother the female at all. But its a lot of observation and if you think you have the room you could try putting 2 females and a male together but you have to consider the other fish again observation to make sure your bettas don't upset and stress out your other fish and making sure your male isn't a nasty #29### where eviction in inevitable.
Do NOT add a female, they can only be kept together when breeding, and this is for a short time, it can SOMETIMES be done with siblings (brothers/sisters) but eventually they do require seperating
If you want a group of Bettas take back ALL your fish and get a group of 5 females
Please take this advice
bananasdoom i know from experience that it doesn't work

and will do anything to stop others making the same mistake