Hi.
Judging by the foot to bin size to fish size, they look a LOT smaller than 24".
Anyhow, they are 100% Channa Marulioides.
And they do look like the Blue type like in MY PHOTO that JayP posted above. (at least credit it dude!)
They max out at around 60-70cm.
Get aggressive as they get bigger and older. (start off friendly little things until they hit 18"!)
From what I can see from your pics, they look to both be males, which is why they are fighting.
You need to provide them cover, it is difficult to keep a heavy planted tank like you normaly would for smaller Channa, but these guys need something to break the line of sight, and to dim the lighting!
Here is an old pic of my male/female bonded pair (one of which is the one JayP posted) see they have some amound of foliage, but importantly, the surface of the water is completely covered in duckweed. This dims the lights (the bright light you can see is from a bulb being shine on the tank for the photo), and makes them feel a little more relaxed.
Tank size is also important, they are very active swimmers, and need space. Mine kept in a 280gal. I think as they grew to max size, they could have done with more space.
