Tettey said that even when they went behind, Norwich felt that they could have won, and having not done so means that none of the players can escape blame.
"It's a very frustrated dressing room - you should have seen how we all reacted," Sky Sports News quotes him as saying. "We were gutted to lose this game.
"After a bright start - and even when they were leading 2-1 - we felt we could have won the game and I think we only have ourselves to blame for this defeat. At the start of the second half we were talking about coming out and being bright again but then we made two mistakes
"The ball just won't go in - it's very frustrating. We played them at home and it was almost the same game - we created a lot of chances but we couldn't score."
The win moved Cardiff off the bottom of the table into 19th.