You ever stand, look at one of your tanks, and notice something seems off? I usually get that from my fishes’ behavior. EVERY time I feed my fish, I do a headcount. That might not be easy to do if you have a really large tank with tons of fish. However, my largest, most populated tank is a 75g with ~20 fish, so it’s easy.
Not only do I do a headcount, but I’ve become so used to their behavior, I can usually tell something is going on within seconds. Though fish can get sick and linger for days untreated, they can also expire quite suddenly, especially if they get beaten to death by a tankmate. Typically, however, you should know pretty quickly when something isn’t right.
If you recall my post a couple of weeks ago about new fish, one of the new fish was a Chalinochromis popelini. It was a juvenile, and I wasn’t sure what the gender was. Anyway, I put him/her in a 75g community tank with other juvenile species. When I fed everyone the night before last, I noticed the popelini at the back of the tank, upright and hovering just above the sand. It wasn’t hiding, per se, nor was it being bullied. In fact, I had not witnessed any harassment at all since I introduced him/her to the tank. On the other hand, the behavior was atypical. Usually, it came out and swam around grabbing morsels of food just like everyone else. This time, it didn’t. That concerned me.
Yesterday morning when I checked on the tanks, he/she was dead atop a ceramic tube. There were no physical signs which might point to an unfortunate tankmate encounter. I knew when I saw him/her that evening that something wasn’t right. My intuition was correct.