Do fish use tools?
Are there any piscatologists or icthiologists out there who can help me. I was watching this little fish for ages yesterday. It was using a piece of grass root or stem to root around in a fold in the pond lining. I watched for fifteen minutes before I eventually went and fetched the camera. It repeatedly probed into the same spot with the piece of grass. Every now and then (1 minute into this clip) it would seem satisfied and do a little glide over the spot fanning its fins. Then it would go back round and root some more. Occasionally it would pull the grass out, quite deliberately, swim round in a loop, drop the grass and then pick it up again near the end and start the process again. Lining the grass up to the hole and then pushing it in, probing into the space once more.
So what’s it all about? I’d love to know…
It seems from the information I have now that this is a male stickleback nest-building – thanks folks. There is a wealth of learned articles out there too about feeding, flow rates and other factors that affect this behaviour.