I have a 10 gallon tank that I recently (2/3 weeks ago) moved the occupants out of into a 55gal tank. Subsequently the 10gal has been severely neglected for that time period. I went in today to sterilized and begin rebuilding said tank. Imagine my surprise to discover to very small fish swimming around in the thing! I immediately did a water change, filter cleaning, and water test. Everything tests normal except nitrates which are high. It is my assumption that these new guys are swordtails, as I have a pair of those. My questions however are the following: When will I be able to tell the species? How often should I feed, if at all? What are the rules for adding fish to babies?, and How the hell did they survive for so long? Any advice would be great. Thanks.