Hopefully someone here can offer me some advise on starting my tank. I we to petco to get the tank the guy knew everything, gave me all the stuff I needed and lots of information about how to start up the 15 gallon tank. Now when I went to get fish I went to super Walmart because it was closer which was a huge mistake the guy knew nothing at all. I got a black moor goldfish and small catfish breed I think it was a pictus. I got them yesterday and today the catfish is already dead! he seemed weird earlier today while swimming sideways and upside and seemed to be struggling. I looked up online and these fish are not even capable for the same tank like the Walmart associate told me! What a dick! Anyway, what can I put with my black moor? And how can I keep him alive better? Is 15 gallons even big even for my moor? I read they need at least 20 gallons now but I really don't want a new tank and really would like at least two fish so they don't get lonely. Any advice at all would be nice thanks