I found a small submersible water pump for pond decorations or birdbaths in my garage. It's about the size of three decks of cards stacked on top of each other. Would there be any harm/benefit of putting this into a 55 gal fw community tank?
well it depends, do you have any small fish? and how is the water cycled in the pump? it needs to be protected so that fish dnt obviously get sucked. before you add it in tho need it submerged in a bucket of water and add several teaspoons of salt; that will kill all the bacteria that may have grown on and inside the pump. leave it in there for minimum 24 hours (just to be sure).
No it should be no problem , but run it in the water before you put in the aquarium ..To clean out the pump..
