for motoros size would be 10-12'' they should be mature or 2-2&1/2yrs old.
Yes they can breed in a 210,,,,,,though not recommended, I've heard of them breeding in a 150 (72X18 footprint) <-------I'll probably get flamed for saying that and everyone will say 48X48, 72X36, 96X48 footprints or larger like a 1,000 gallon tank.