Also, it is too early to tell the sex unless it is well colored. If it has bright orange in the belly region and along the dorsal fin, then it is a female. If not, it does not mean it is a male. Females with little or no orange coloring can be determined from the top and bottom fins. When they reach 1 1/2 to 2 inches, the males fins will grow long and pointy at the tip. The fins will reach to the end of the tail. Females fins will remain rounded on the tip and will not reach to the end of the tail but just past the base.
A convict generally does not reach the agressiveness as when it is paired up and defending territory or fry. They will however pair up with non-convicts so be watchful of changing behavior.
Also be watchfull of ragged fins of the tankmates or even the convict. Separate them if this occures because this is a sign of extreme aggressiveness while you are not there.