if your bettas are dropping left and right from dropsy in a divided tank id be cautious..sounds bacterial to me and id likely treat the tank before adding any other fish. severe bloating (that can present itself like dropsy) can also be internal parasites...also contagious if the poo is spread around between compartments and they suck it up (which bettas tend to do as they are so curious)...just a bit of advice.
best of luck
cheers
Bloating can be caused by parasites? I didn't know that. I thought it tended to present with a sunken belly. That might explain why the meds (which I have been using since they seemed off colour weeks ago) didn't work.
I have a wormer in the cabinet - I'm going to do a major clean out and treatment blitz before I add anymore fish, so do you think I should treat with this instead, as a precaution? The sick boys (actually, Boann died today) have been moved to a hospital tank and the others all look OK.
Can the anti-bacterial and the wormer be used together? Might help cover both bases.
Once everything is OK, do you think guppies could work? Or endlers?
internal parasites can indeed be sunken belly or being bloated (and many conditions present themselves in contradictory manor, which is why it is difficult to be 100% accurate in a diagnosis when it is a sneaky illness). think of it this way, if their abdomen is full of worms which are either eating the food the fish ingests, or living off the fish's tissues themselves, you can have a really skinny fish, with a hugely bloated belly (ie the fish isnt getting nutrients becasue the parasites are using up his food before he does, the fish takes from his body reserves and gets skinny, you feed him more becasue he looks skinny and that gives the worms more food, they multiply and then his little belly is crammed full of them making him look fat but really he is starving. also, different internal parasites may cause different symptoms (ie worms vs say trematodes)...thats why there is a confliction)
what med WERE you using and what were you intending to treat for? did your other guys die of "dropsy"? what were their symptoms? many times a fish gets bloated, his scales around his belly pinecone(simply from him being so bloated that his scales lift in that area. slime disorders can also raise the scales slightly, but of course this isnt dropsy) and he dies, and folks say-its dropsy..well, dropsy is sort of a symptom (bloat/pinecone) from any number of underlying things. TRUE dropsy is organ failure which is 100% incurable.
im not sure if antibacs and wormer can be used together. did you notice their (or you existing guy's) poo? did it look normal or any white,stringy,mucousy poo? inflamed anus? flicking or rubbing (which is sometimes a sign of internal parasites also). sometimes internal parasites will casue the bloating to be "uneven", where one side of the belly sticks out a bit more than the other when viewed from head-on. have you noticed that?
it really is just a shame about you and your bettas. you seem to have absolutely no luck with them, which is why i suspect bacterial over anything-far more easily transmitted thru hands between tanks and equipment than, say, worms or other internal parasites. however, if you bought all your stock from the same place, it could indeed be internal parasites from their source. so its a tough call.in your shoes i would be tempted to deworm first, then try antibiotics (dewormer isnt as harsh as antibiotics on the fish so id try the milder treatment first. and just make sure you up the aeration in the tank when treating with the antibacs...
hope all that long rambling made sense and was at least a bit helpful. any more info/questions feel free to ask. sad when your fish are sick
cheers
and PS- id worm everyone just to be on the safe side..even the ones that "look" ok. and wormer is a fairly "safe" med (wont harm inverts/plants/etc)
