Hi. I am a fairly new aquarium owner, and I am looking for some advice.
1. I have a 75 gallon tank that has been set up since Nov 25, 2015. (photo attached)
2. In my tank I have:
-5 rainbowfish (2M, 3F) (added 30-Jan-2016)
-1 redtail shark (F) (added Dec 2015)
-1 opaline gourami (F) (added Dec...