Neon Tetras, Paracheirodon innesi, are commonplace fish these days perhaps, but they are still one of the best and most peaceful tetras for a small aquarium. However, getting them healthy, now that can be a challenge.
Neutral to acidic water conditions with plenty of hiding spots will serve these fish well. Best kept in schools; I’d never encourage you to order only a few unless you’re adding them to an existing population. They are also not as robust as other tetras; I’d refrain from adding Neon Tetras to new aquariums, instead save them for a more established tank.
Don’t confuse the Neon Tetra with it’s slightly larger, more colorful, and more expensive relative, the Cardinal Tetra, Paracheirodon axelrodi. You can easily tell the two apart, as the red coloration on the lower flank covers the entire belly of a Cardinal Tetra, whereas the belly of a Neon Tetra is silvery.
When Neon Tetras are offered here at MiniWaters, they have generally been on hand for at least a couple weeks, but often longer, to ensure that the fish we sell are in great condition. Remember, this is a small tetra, and at maturity is just around 1″ in length.