Mandarins do get large! I’ve seen the small captive raised babies at 3/4” for sale. I’ve seen adults at 4.5”.
If willing to put extra time into a small tank and raise brine shrimp, dwarf seahorses are cool. Lots of personality in 1/2”-3/4” size. You could get several in a tank that size
If willing to put extra time into a small tank and raise brine shrimp, dwarf seahorses are cool. Lots of personality in 1/2”-3/4” size. You could get several in a tank that size