On the evening of June 27th, I purposely arranged some marbles on top of a piece of travertine tile in one of my Julidochromis dickfeldi species only tanks (see photo above). I use these flat, glass marbles for stacking travertine tile to create additional refuges for fry and juveniles.
I began to notice at least every other time I did a water change on this tank, many of the marbles were no longer on the tile. They’re being moved. I have not personally witnessed this, but there is no other way they can physically move off of the tile. There is little current to speak of in the 20g long tank where they reside, and no one in the house other than me puts their hands in the tanks.
Furthermore, I believe the marbles are too heavy for J. dickfeldi juveniles to move, so I have concluded it has to be one or more of the adults. Because I haven’t witnessed it, it is possible the marbles get knocked off from the fish being aggressive with each other, though there is absolutely no physical indication of aggression.
As shown in the photo at the top and to document this, I arranged all of the marbles onto a single piece of tile. On July 11, I took the photo below. Though I am sure I may have slightly moved the tile during a water change, I certainly didn’t knock the marbles off.
Is this accidental, play, or some other behavior? Perhaps the adults don’t like the marbles (either their location or their appearance) and are moving them off the tile so they’re on the bottom of the tank and out of regular view.
Cichlids and play are something I have blogged about before. I first posted about this phenomenon in 2017. Here is a link to one of the articles I cited in that piece. Since that initial post, I have posted about play and/or enrichment four additional times:
- Cichlids work and play (2020)
- More on cichlids and play (2022)
- Do cichlids play – revisited (2022)
- Some care, some don’t (2023)
I have long been a proponent of cichlid enrichment (e.g., providing moveable objects in a tank and/or adding/changing the decorations/structures in a tank periodically) as opposed to bare tanks. There is scientific evidence that enrichment changes behavior (e.g., reduces aggression) and cognition in some cichlid species. If interested and you want more details, I would recommend you go to Google Scholar and search for “cichlid enrichment.”