Depending on what river and geographic location, it could be a couple of species, but it looks more like a feral female. Feral populations occur when fish that have been domestically kept for generations are released or somehow escape into waters where their species does not normally occur. There are many feral populations of various species around SE Asia due to fish breeding operations being sloppy.
Hi.Today I went to the same river and caught some bettas.Again,I need your help guys.The white one is a male and the red one is a female.I am quite sure that the white one might be either a crown or comb.The red one,I am not sure,may be a half moon or veil tailimage.Can anyone help me to ID the both bettas?image
Aquaphobia was right.That river consist of naturally existing fresh water fish and some fish that their owners let them go into the river.Even I saw some giant flowerhorns there although they don't naturally exist there.Perhaps the white crowntail might be man made variety and they breeded there and their population increase.By the way,I got a new betta home today from the river.Guess who?The crowntail of course HAHAHA!
Yes, they are feral populations, though it must be a relatively recent release, as I doubt that crowntail would last long enough to breed. Feral populations tend to devolve back to the natural forms, like the females, as these are usually the dominant traits in the species.