ArnieStinger
Fish Fanatic
The puffers are semi-brackish fish and your very hard water is probably helping them survive without the salt. The betta splendens is definitely not a brackish fish but mine have shown a huge ability to adapt to differing tap water conditions. As long as you have only one tank, fish that different in their needs will be asked to adapt quite a bit.
You're right. I think the fact that the betta is breed from london and it's last owner was 3 or 4 miles away would mean that the water would still be very hard, the betta and the puffers are probably well adapted by now, I think they are at least a couple of months old, if not 7+? Long enough to adapt or perish I would think.
Im 100% sure the water conditions are better than their last tank, the last owner did not use salt, a filter, clean the gravel or change the water often.

getting bloated is not at all good for them. They need about as much as the size of their eye in one sitting so I feed two betta pellets twice a day.
( No shes actually angry and bit him the other day )