I love the Diamond Tetra! Pretty and peaceful, but a tetra that still gets large and puts on an impressive display in large groups. That said, they’re often not all that attractive when you see them in the aquarium trade, being sold as juveniles. At times, they can come in looking a bit rough.
If I’m offering Diamond Tetras for sale, they’re from one of two camps. Either juveniles which are well conditioned for a couple weeks prior to sale, or the are mature adults which have been grown out for several months.