Another filtration question and more "overkill" answers. Obviously, the more filtration the better but an fx5 has enough flow and room for enough bio media. You'll be fine as long as you do water changes. You'll learn real quick if you hang around this forum that everything is overkill. I'm sure you'll get flamed about being overstocked too. The truth is that there are a lot of memers on here that don't practice what they teach and just like to jump on the bandwagon and flame someone who seems inexperienced. Youre fine as far as filtration goes. Stock may be an issue with fighting and territory, but only time will tell. There are no black and white answers in fishkeeping like the majority of the people on this site believe.