They are two different things, but a counter of jellies harvested would make sense I guess. Alternately, it could be countdown like the goth kid fights, but that only works if they are actually regularly spaced, which doesn't seem to be the case. (Speaking of which, the stomping boots could actually use such a countdown, since those are regularly spaced).
Also, the sea jelly could be added to breakfast, since there is no opportunity cost to it or anything, and it would save people making daily deeds. (Dunno what category it would fit under, it's not a once per day item use, though that one still is the closest, sort of).
Edit: I have already added the following to my login script, I might as well share it. I don't know if this is the only or the best way to do it, but it works nicely. (This doesn't actually change back to your previous familiar which might be a good idea addition):
if ( have_familiar($familiar[Space Jellyfish]) && !get_property("_seaJellyHarvested").to_boolean() )