Think as long as the fish you add are as big as the six line or bigger you should be fine, maybe just as aggressive or more but think it’s hit or miss there. Body shape may be a factor to consider as well as color and patterns.
All depends on the personality of the fish, my six line is 2.5-3” big and definitely male but doesn’t bother anyone in the tank but he’s in with a pair of blood orange clowns and a coral beauty angel.
Never had fire fish but want to say I’ve read of other people having issues mixing the two. Seems highly possible to have issues adding the fire fish after the six line. Wouldn’t think it would bother the chromis but not sure I would buy multiple, they tend to pick each other off especially in small tanks from what I read.
All depends on the personality of the fish, my six line is 2.5-3” big and definitely male but doesn’t bother anyone in the tank but he’s in with a pair of blood orange clowns and a coral beauty angel.
Never had fire fish but want to say I’ve read of other people having issues mixing the two. Seems highly possible to have issues adding the fire fish after the six line. Wouldn’t think it would bother the chromis but not sure I would buy multiple, they tend to pick each other off especially in small tanks from what I read.