It's actually still an infant (is that the correct term?) and I was hoping that I could determine the gender before getting another opposite gender so that they breed. But I guess it's fine now since I already got a second one...
You might be looking for the term "hatchling". It's generally not a good idea to breed them (invasive, overpopulated, abandoned, expensive etc) but male RES often need to kept alone in their own tanks.