is the fire fish the only fish?
in a 20 gal
my suggestion would be to add one or two. Read up on each fish first
- bangi cardinal
-red sea mimicblenny
-rainfords goby (not typical goby)
- flasher wrasse
- pink skunk clownfish (you could put in a pair)
- flame hawkfish
- royal gramma
if you wanted a predator tank
some waspfish,stone fish or scorpion fish are cool.