Hi all, I hope this isn't too awfully stupid of a first question.
I recently inherited a 50 gallon tank from a friend. I got it all set up with a super good filter, a heater, rocks, etc (my "free" tank has turned out to be very expensive), and yesterday I went to the pet store. The guy there told me to start out with only a few fish, because after a week or so it will go through some bacterial phase and turn milky with ammonia.
This sounded fishy (no pun intended) to me, as my fiance and I previously cared for an aquarium in one of our apartments that was in such bad shape uppon our arrival that we had no choice but to completely empty it, scrub it clean, and re-fill it. We did so, putting all 20ish of the fish back in at once, and nothing bad happened. But I decided to err on the side of caution and get only four fish.
I got a Sunset Gourami, a Powder Blue Gourami, a Tiger Barb, and a Bala Shark. The pet store employee said that all of these fish would cohabitate peacefully. The Gouramis and the Bala Shark are perfectly happy, but the Tiger Barb is a malicious little troll. After less than 24 hours in the tank, he is mercilessly harassing the Gouramis, nipping at their fins.
What should I do about this? Is he acting out because he's lonely, should I get him some more Tiger Barbs? Or is he just a butthead? Should I see if the petstore has a return policy and bring him back, or see if I can give him away or something?
Any help is appreciated.