In my tank there wouldn't be an issue with just leaving it there and letting the clean-up crew do their job with that small fish. However, in a 14-gallon tank I don't know. It will eventually disintegrate and cause ammonia. I am assuming things could go bad quickly with such a small tank. If it were me and I couldn't get it out, I would just test the water a few times a day to make sure you are not getting any spikes. If you do start to get a little spike then have pwc water available and do a pwc asap, as needed.
In a 14-gallon tank, I can't imagine it being too hard to just take the few pieces of rock out and remove the dead fish manualy. That would definitely be the safest bet and probably less work in the long run considering all the testing and pwc.