At what point is heat not needed for Bettas? (in tropical environments)

SO I've only lived here for 2 years.. on an island pretty much.
SO I'm used to having winter and freezes and Spring freezes as well..
Well I have my tanks with heaters..
but I've noticed that even on the COLDEST days here..
even when our house heat was out (we used the dryer occasionally and the apartment got HOT)
tubs I have with plants growing out in them.. and no heat.. do not get below 72-73. (and these are shallow tubs with a few inches of water)
I'm experimenting..
but seems like generally w/out heat water here inside stays around 74.
So would bettas need individual heaters?

 

Bettas should be in warmer water. I would aI'm for keeping the tank at at least 78 F.

 

Well maybe I need to check his tank again.. because I have been trying to (unsuccessfully) lower the temp in my 20 gallon for my rcs/pygmy cory and otos..
and last night unplugged it to see what it gets to w/OUT heat..
and after overnight w/lights off and no heat.. its still at 78.

 

Depends on what kind of Betta and what you want to do with them. Betta purchased from large pet shops, e.g. Petco, Petsmart, etc, are the most cold tolerant. Some males even build bubble-nests in their unheated cups of water ~70F. Betta purchased from AquaBid that are imported from Southeast Asia need temperatures ~10F higher than that to construct nests.

Desired longevity also needs to be taken into account. Betta kept in cooler water live longer vs those kept in warmer water. Breeding Betta will require higher temperatures. Fry grow-out tanks should IMO be maintained at higher temperatures at least until the juvenile stage.

This is assuming Betta splendens, the other Betta sp are a different story.

 

He's a betta splendens from a local LFS that was being kept in a cup.
I'm not interested in breeding him but would like him to have a longer/higher quality life.
he does build big bubble nests as is so I suppose he's fairly happy?
And at this point with it just now going from winter to sprint here (getting used to this tropical climate)..
and our central ac being out in our apartment (landlord issues... we have one window until for now, in our bedroom, theses tanks are in my kitchen/living room)..
seems w/out heat the 20gal is staying at 77 ..
so I may need to get a fan or something for it for now.