I crrently have had a tank for about a year or more. We won two goldfish at the fair and wanted to get them out of their environment, so my ex-girlfried and I took home two. I knowing nothing of stocking, just got a filter, some water additives, gravel, etc and made a tank and so far it's had only one issue. Well, I am going to start my 90 gallon tank this week, and want to learn alot before I start. One: I have a goldfish and a common plecco right now. I don't want to kill or lose them so I am wondering what else I can put in WITH THEM to spice it up. Also, what are the most important pieces of stocking? I have the tank, the filter, the lights, so there is no changing those in the near future ($$$ issues). It's 90 gallons with C360 filter and two long tube light I think they are fluorescent. I want to know what type of fish can coexist and does the type/color of gravel matter?