Hi, I have a betta fish. 
Those fish are great! They're small so you don't need a big aquarium and they have such beautiful colors!
I agree, they also dont need much food so they are low maintenance (unlike my wife).
Ha! Bettas are also known as Siamese fighting fish! Hopefully also unlike your wife!!
Siamese fighting fish? Can you tell me more about this? 
These fish are extremely territorial! They have extremely high levels of aggression toward each other. That's why they're always kept alone in their bowls.
I see, perhaps they might serve better as food than pets. Would you agree?
if they are housed in too small an aquarium. It is typically not recommended to keep male and female bettas together, except temporarily for breeding purposes which should always be undertaken with caution.
This species is native to the Mekong basin of Thailand, Laos, Cambodia, and Vietnam and is mostly concentrated in the Chao Phraya river in Thailand. The fish can be found in standing waters of canals, rice paddies and floodplains. It is listed as Vulnerable by the IUCN.
Description.
"B. splendens" usually
Siamese fighting fish
The Siamese fighting fish ("Betta splendens"), also known as the betta, is a popular fish in the aquarium trade. Bettas are a member of the gourami family and are known to be highly territorial. Males in particular are prone to high levels of aggression and will attack each other if housed in the same tank. If there is no means of escape, this will usually result in the death of one or both of the fish. Female bettas can also become territorial towards each other