Online vendors like to give their customers little extras, added to their order. But owners of small tanks should take the time to politely request "no extras please". These are the reasons:
* They may send as extras a species of fish that cannot live in a small tank.
* They may send extras of the same species that you ordered, but lead to an over-stocking situation.
* If you order one specimen animal it can't breed, if they add another you may end up with a breeding pair providing unwanted eggs or fry and a population that quickly booms out of control.
With a small tank, less is more. So when you have worked out exactly what you want, and if you decide to order online, be sure to specify "no extras please"!