Hardy fish for a 5 gal ?!?!?

Betta! they're probably the one of the hardiest fish you'll get, but they do require a heater like others have stated.
 
I would go with a betta or a nice plant. Guppies (1-3) or some kind of tiny mollie would also possibly work. Just stay on top of water changes.
 
Really? That's odd...don't dwarf puffer require live/frozen food and many water changes because of their messy eating habits? Probably not the best since its for a beginner.
I agree with this. DP's are sensitive little guys. I'd also go for a male betta, or an RCS tank.
 
But how about a pair of betta ?!?!
Not in a tank that small. The male would beat up the female and she would not have anywhere to really hide.

You could probably do a couple of female bettas if you want more than one fish. White clouds come to mind, but I am not sure if they would prefer too big a school. A couple of male endlers might also be an option.
 
how's about some celestial pearl danios? I've found them to be tough little guys so long's the ammonia is 0.0ppm
 
Not in a tank that small. The male would beat up the female and she would not have anywhere to really hide.

You could probably do a couple of female bettas if you want more than one fish.

A 5g is much too small for a betta sorority, which requires an absolute minimum of three females to work.
 
Theres a perfectly good fish out there that lives in coldwater. GOLDFISH!
 
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