Originally Posted by Enkil
For some it is. I judge based on the fish.
I tried to move my Egil to a smaller tank. He ate his tail. I tried moving him to a bigger tank. He completely destroyed his tail. Put him back with his brothers and now he's fine. -_- Still nibbles his tail from time to time though. I wouldn't dare give my Odin more or less space. His vision is too poor.
I would feel bad putting Hannibal in anything less than 3.5 gallons. He has a body that is over 2 inches long with at least 3 inches of fins. Cranky little thing.
Do Egil and Odin have about 3.3gallons each? (10gal divided 3 ways).
I personally wouldn't put a regular sized betta in less than 2.5 gallons, and I wouldn't put a giant or king in less than 5. But for those that keep their betta in one gallons, I think it's perfectly fine if you care for them properly...