Normally, I don’t keep anything other than cichlids. This means I typically don’t have dither fish or other schooling fish. However, because I am preparing for some new cichlids and I have a couple of sparsely populated tanks, I wanted to boost the beneficial bacteria in their respective filters.
Why boost the bacteria? Taking a tank from a single, small species to as many as 10 or more medium-large species substantially and quickly adds to the bio-load. To effectively handle the expected bioload increase with the new cichlids, I got some giant danios (Devario aequipinnatus). I put several in a 20g tank that had one occupant. I moved that occupant to a larger tank, leaving the danios as the sole species in the 20g.
Another tank, a 45g, was holding a single Neolamprologus similis, so I also added several danios to that tank. I will be moving the similis to a smaller tank soon and thus needed to increase the bacteria here as well. What fascinates me about adding the danios to this tank is the enormous behavior change with the similis. It’s an adult female, and she is much more active now. Before the danios, she would rarely venture very far from her shell and would never get up into the water column. Just last night when feeding, she was up in the middle of the school of danios. It took me a second to pick her out of the crowd. The danios are nowhere near full grown, so they’ll all about her size.
Her change in behavior has been astonishing to watch. Though my intent by adding the danios was not for them to serve as dither fish, that’s what they’ve become. I have had dither fish in the past, but never experienced a behavior change in any cichlids like this. Perhaps it’s because the similis has been the sole occupant of her tank for a while. Dither fish, via their behavior, are supposed to put other fish at ease. I can say, at least in this case, the danios are achieving their purpose.
If you have some shy cichlids, try adding some very active schooling cyprinids or characids to the tank. You might experience a behavior change like I have.