The enigmatic zebrafish

Working with zebrafish in these recent weeks has been a genuine challenge. As I wrote in my previous blog post, the exceptionally simple procedure we used weeks ago did not work. Surprisingly, we saw no evidence that the fish were more interested in investigating new objects over familiar objects. In fact, the data seemed to suggest the opposite trend – that the fish prefer familiarity rather than novelty. We greeted this idea with healthy skepticism because previous research has shown that animals prefer novelty.

Guided by this knowledge, we opted to use the novel object and novel location procedures again except this time with a computer monitor. It was clear from the footage that the previous procedure was too stressful, so this procedure allowed us to minimize disturbance to the fish. Bailey and I would simply place an individual in the test tank with a computer monitor flush against the side, press a few buttons on the laptop connected to the monitor, hit record on the camera, leave the room, and wait. One can see why this procedure is attractive: it requires little work on the part of the researcher and minimizes stress for the fish left alone with a computer monitor which displays objects in a non-aversive manner.

After meticulous footage analysis and data compilation, we saw no convincing trends. The fish did not behave any differently around a newly displayed object compared to a familiar one. At this point, we examined the procedure and considered something we had overlooked: perhaps the fish are constitutionally unable to remember two objects for an interval of 5 minutes. If both objects in the test phase are new to the fish, then the fish will treat them as such and investigate them both with no preference for one over the other.

So we tried removing the 5 minute interval between the familiar objects and the novel objects. Again, we did not see the trend we expected. Still, no preference for novelty, nor a strong preference for familiarity. The NO procedure is attractive because of its potential to be used in high-throughput screenings. It proved to be an efficient procedure for measuring learning and memory in rodents, but as it is turning out, it does not seem to have much translational value for behavioral testing in the zebrafish.

As Thomas Edison once said: “I have not failed. I’ve just found 10,000 ways that won’t work.”



  1. lmsevier says:

    Hi Alex, Awesome work! Sorry that the experiment didn’t work. That must be frustrating. But, the work that you are doing is super important!

  2. Your project sounds really interesting. Though we both do biology research, we’re on different ends of the spectrum. However, I have a question for you: how do you feel about inconclusive evidence and what drives you to keep trying different things?