A 125 can be used temporarily. I have three 8-10" motoros along with several other fish and water is just fine. I have tons of bio filtration and never go more then 48 hours with out a 50% water change, so it can be done temporarily. I wouldnt recommend it if you are not up to that.
A small male motoro pup could COMFORTABLY live in a 125 for a year maybe two. Just make sure you have a good understanding of water chemistry and good maintenance habits!
Most cichlids are a no-no but some are ok.