This 2019 video from Japan is called Top 10 wild betta species.
From the Bangkok Post in Thailand:
Fish with national flag hues fetches record price
14 Nov 2016 at 15:51
Its price started at 99 baht and the winner took it for 53,500 baht.
That is over 1400 euros. The old record was 600 euros.
Thairath Online reported that Mr Kachen, a vendor who raises halfmoon Betta, or Thai Pla Kad, was surprised with the final price because to date a beautiful halfmoon Betta fish fetched four-digit prices at most in auctions.
People had long bred Siamese fighting fish with a Thai national flag pattern but his fish might be special because of its colour pattern which clearly resembles the Thai national flag, Mr Kachen said.
Thairath quoted Chuchart Lekdaeng, the new owner, as saying he named the fish “Trai Rong”.
Trai Rong, literally meaning three colours, is also the name of the Thai national flag.
Mr Chuchart, head of an ornamental fish group in Nakhon Pathom province, said halfmoon Betta rarely had a clear Thai national flag pattern, and he thought the one he had just bought became the most expensive Siamese fighting fish.