They don't seem to be moving on their own, but they're in the current from the filter. Some are very tiny, but others are about the size of a pinhead. Perhaps slightly larger. Hannibal also doesn't seem quite as bloated now. Could these have come from him? o.O
No. I tried not to move anything except his heater. I even moved that sparingly as moving it seems to stress him now. Whatever they may be, they worry me. So I'm going to do a full tank cleaning with 100% change tonight once Devon gets home and can help me.
When I clean it, should I leave his gravel and plant out to better monitor him?
Yes, if you can, it would really make it easier for you to tell if he's pooing or not if the tank is barebottom. If the white specks show up again after a 100% change and with no gravel in there, I might wonder if he DOES have an external parasite problem but he's just not rubbing or darting. Not all bettas who have had gill flukes exhibit that behavior.
Yes, hot water usually works pretty well. You can also use hot water and vinegar but in this case, I think hot water should do the trick.
If he had gill flukes, that would explain him not being able to close his gills properly. But he also might not be able to close them because of scar tissue from ammonia burns. It's hard to tell. When you say his gills are black, do you mean the little beard part that comes out when they flare? Because underneath the gill flap, the actual gills should be a healthy pink-red color. If they are a dark or bright red or greyish/white, then there's cause for concern.
Hopefully, the white specks are just something that either came from the filter or from the gravel. We'll keep an eye on them. And that's funny Hannibal loves his filter so much. Most bettas hate/tolerate their filters.
Got things cleaned up.
Hannibal looked completely better last night after I got done taking a shower. This both mystifies and worries. I have seen the calm before the storm in other animals and worry what this might mean for him.
However, he ate his blood worms today without a problem. Even the oddly shaped ones he pulled from my grip. He's also been resting on his plant like normal again.