Can salt treantment cause this?

[happychem]

They still have they're swollen stomach's today, but, not any worse than yesterday and they are all swimming around quite happily, it really doesn't seem to be bothering them.

Incidentally, and unfortunately I lost this point in all my ranting and raving, I've heard (but never observed personally) that fish can occasionally, when being particularly greedy, swallow air bubbles that can take some time to work through their gut.