May I ask Why tropical ? Most tropical species will outgrow a 100g. Subtropical saves you the heating requirement and opens the door for many more attractive and appropriately sized species .
Lol that's why I asked! Stock won't last either way.
A solo Aurantimaculata would be quite happy for life in a 100g tank . Even a pair would be ok. My pair were raised in a 4', 100g right up until this years breeding. It was still plenty of room for them but I expected aggression when the fry were released ( not to mention several hundred little mouths adding to the bio load lol) so when breeding hit I upgraded them to a 6' 160g, in the end I still needed a divider for a couple months. I'm sure they could have remained in the 100g , just have a divider ready in a couple years if they start breeding.
