there are two major issues here. first, krill is a very poor diet for puffers and has no nutritions. it has been reported and studied that feeding a krill-intensive diet causes a "lock jaw" condition, where the puffer cannot open and close its jaws anymore. the end result is the puffer dying from starvation.
i am not sure what "clam strip" is but it does not sound like a proper diet either.
second, there does not seem to be shelled food being fed to the puffer. puffer's teeth continuously grow and need food with hard shells to grind down the teeth, otherwise they will be overgrown and cannot eat anymore. if your puffer has overgrown teeth, you will need to manually trim them or clip them with nail clippers.
please do more research on proper puffer food; they should be fed with marine-based food such as clams, mussels, shrimps, squid, scallops, etc. i highly suspect your puffer has the lock jaw condition, and you will need to force feed him now with the proper food soaked in vitamin supplements, and hopefully over time the lock jaw will reverse.
