Can Convict cichlid Live With Green terror?

Two separate problems point the same way. A 30 cm green terror is twice the length of a 15 cm convict, and the green terror's own profile says not to keep a breeding pair in a community tank at all, since a spawning attempt turns violent toward whatever else is nearby. A convict, itself a combative fish, is exactly the kind of neighbour that draws that reaction.

Water settles it further: the green terror's range tops out at 24 °C and the convict's starts there, so the two only meet at a single degree, not a workable overlap for either fish long term.

Keep them in separate tanks. If you want a large, robust Central American companion for a convict, choose one closer to its own size and temperature range; if you want company for a green terror, its own profile calls for an enormous tank, 650 litres or more, and other similarly large cichlids rather than a fish a fraction of its size.