I saw the fish flopping around on shore and thought it had somehow been stranded.
It had been caught by the snake. I got too close for the photos and it slipped back into the water.
So, I do not know if it was able to swallow the fish.
Update on June 16. In the same pool, now evaporating, one snake had caught a smaller fish. Two others tried to take it away.
The 'owner' snake tried the escape to dry ground but was followed by one of the others. They ended up wrestling back in the pool.
The fish seemed to have been lost in the battle.