This movie comes at you in more than one direction. Humans can suffocate both physically and mentally and Jaffe Zinn has offered us a perfect story showing both sides of suffocating.
Here we have a small community in a most rural area of Idaho. Most of the adults are concerned with working to meet the needs of maintaining a comfortable life as we see in the Jerry Garabrant character. His wife Martha, is too busy tending to the dogs needs, shopping, house duties, to notice that their daughter is not home. Then there are the teenagers seeking risky thrills to alleviate their cramped existence in an isolated community. Each one is suffocating mentally and is mostly unaware of it.
TJ, the main character in this story, is visibly tormented, but why we do not find out until well into the movie. Is he suicidal? He wants to talk to someone but is not capable emotionally. The two little boys playing outside discover something that brings the viewer to the direction of this story. The physical side of suffocation is shown with the dead fish and in what the two little boys discover.
About the ending ... some find it pointless. But I see it as just saying 'life continues'. We all know the fate for TJ, the Garabrant's will eventually recover, and few things will actually change for all living in that small community. Zinn has made a thinking persons movie, beautifully photographed, scripted, and acted.