How much should i sell this red devil?

[Gordo124]

Bought a red devil cichlid about 4-6 months ago when it was like 3.5 or 4 inches now it is like 5-6 inches... I think it may be a femal because the horn is not growing and at the same time it may be a male ecause it is very aggressive!
It killed my blood parrot for no reason!!!
So i need to sell him! How much would he be worth now?
When i first bought it, it was $19...

 

[emerald76]

$25 I Think would be decent

 

[Gordo124]

Oh really? Good vuz i was thinking maybe $25-30