New to cichlids; How fat do firemouth's grow

Ive had my FireMouths for about 3 1/2 years now, and the biggest male is only 4 inches, my other male is 3 1/2 inches, and my female is 3 inches. They do not get much bigger than this. FireMouths are generally a smaller breed of South/Central American Cichlid and dont get much bigger that 5 inches at most.
 
I would guess probably female, but either it is fairly small, which makes the guess pretty shaky, or that is a huge plant behind it :)
 
When I got my firemouths they were about that size and I only got 2, guessing and hoping to get a male and female and did, but honestly that was 75% luck.
 
Just noticed my Firemouth doesnt like my larger tiger barb when they cross pathes. May have issues in future after all. Well this is trial and error for me. Still new to cichlids. My Krib is doing exellent though. It fits right in.
 
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