Single.
This. Even theoretically bonded pairs often dissolve after about 4 months leaving just one.
The pair of clowns will take ownership of the whole 15 gallons.
I would go with a pair, but only if I put them together myself and am certain that I got a male and a female.
So nice of you to volunteer to pick out a pair for him.
I would go with a pair, but only if I put them together myself and am certain that I got a male and a female.
How would you be sure of that? Firefish are not sexually dimorphic, so telling male from female would be guesswork at best.