It's been almost 18 months since I posted on noise in aquariums, but I was reminded of this problem again the other day. As I was doing some work, I noticed a constant humming sound coming from above me (i.e., from a tank in a room above where I was working). I had just completed a water change nearly 30 minutes prior, so I suspected the sound had something to do with that tank maintenance. I went upstairs to look and a powerhead was vibrating badly, which was resonating through the tank, the stand, and the floor above where I was working. I was able to adjust the powerhead to reduce the vibration, which subsequently reduced the humming.
If that sound was noticeable enough to bother me, imagine how the fish in that tank felt. You're probably wondering whether such sounds really have any impact on the fish. After all, fish are bombarded with sounds constantly in the wild just as they are in captivity. I posed that question to Dr. Karen Maruska at LSU when I interviewed her recently. Dr. Maruska studies the effects of noise on captive fish, including cichlids. She indicated in the interview that most equipment sounds (e.g., filters) in aquariums are in the low-frequency range, which have a greater probability of affecting fish in a negative way. Her research on this is ongoing, but she indicated that there are published studies that discuss some of these detrimental effects.
So here is a small bit of advice for lowering vibration noise if you use external canisters for filtration. Fold a towel and set your canister on top of it so that your canister is no longer making contact with the solid surface of the floor or cabinet. The towel will dampen much of the vibration caused by the canister. Use a light colored towel also. This way you can easily spot a canister leak before the towel becomes soaked. A light-colored towel darkens when wet.
The Cichlid Room Companion
Tropical Fish Hobbyist
American Cichlid Assoc.
African Cichlid Hub