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The Cichlid Tank at the JMZ

March 7, 2023

Hello Friends,


While it may not feel like it with the recent cold and rainy days, spring is in the air at the Palo Alto Junior Museum & Zoo. The flamingos’ breeding season has already begun, and the zoo is welcoming new animals. A colorful military macaw, a threatened species, just arrived at the zoo and will participate in the JMZ’s Ambassador Program. As Canada thaws, a meerkat princess will soon arrive at the JMZ, creating one of the newest meerkat bloodlines in the country. As we get ready to welcome the new season, we dive into the zoo’s vibrant fish exhibit with JMZ Executive Director John Aikin for this month’s newsletter.


March is also Women’s History Month, and the JMZ is celebrating with a new traveling exhibition Picturing Women Inventors organized by the Smithsonian.* On March 21st, the Friends will host a free event for JMZ visitors: a story time for preschoolers, featuring books read by the Friends of the Palo Alto Library, and an activity on "Inspiring Women" from 3 to 4 p.m. Tickets to the JMZ must be purchased in advance. You can find more information about these and future events on the Friends’ Events page.


I hope to see you at the JMZ soon!


Lauren Angelo

President, Friends of the Palo Alto Junior Museum & Zoo

Exhibit Spotlight: JMZ Fish Tank

Questions for John Aikin, JMZ Executive Director


What is unique about the JMZ’s fish tank?


The fish tank was inspired after a visit to Busch Gardens in Tampa, Florida. The hippopotamus exhibit there is home to hundreds of Lake Malawi cichlids in various vibrant colors. The tank is positioned so that visitors face south looking into it. This allows light to shine through and illuminates the water all day, and it is gorgeous. We wanted to recreate a similar experience at the JMZ— without the hippos! Now, the JMZ’s cichlid tank is probably the largest of its kind in Northern California.


Large fish tanks are incredibly difficult to construct. There are multiple layers built in the process in order to ensure there will be no leaks once filled. It takes a lot of time and specialized knowledge. We really wanted visitors to feel like they were underwater with the fish when the tank was built. The acrylic barrier that contains the water is actually slightly concave, which gives the illusion of being underwater and closer to the colorful fish inside. Our tank is roughly 6,000 US gallons.


Not only are these tanks hard to build, but they are also difficult to maintain. The cichlids inside have their own unique care needs and environment that has to be monitored. We actually have specialists visit every week to check the water quality for the fish! We hope to introduce turtles into the aquarium sometime in the future, which is why the artificial branches in the tank are vertical, so that turtles cannot escape. Fly river turtles are a great option for the tank since they enjoy the same warm, alkaline water that our cichlids do. 

Photos of the colorful cichlids inside the tank.

Can you tell me more about the different cichlids in the tank?


Lake Malawi cichlids are a textbook example of adaptive radiation and evolution. Cichlids are found in Africa, South Asia, and Central and South America. In Lake Malawi in East Africa, cichlids have diverged into at least 850 different species. The fossil record indicates that throughout history, Lake Malawi was inhabited by very few cichlid species, unlike today. Lake Malawi is isolated from other bodies of water, so all cichlids in the lake most likely evolved from random mutations. This is a great introduction to evolution for our older visitors.


There are more than 25 species of cichlids in our tank, representing a rainbow of colors. Some cichlids are common, like the yellow lab cichlid. Others, like the Moor’s cichlid, also known as the humphead, are vulnerable species. It is pretty exciting that we have been able to add rarer species of cichlids to our tank since opening. As mentioned previously, we have specialists monitor the water conditions in the tank, so our cichlids remain happy and healthy. Cichlids are so vibrant, they almost look like they belong in a saltwater coral reef, but they are actually freshwater fish! We feed the cichlids a primarily vegetable diet. Cichlids are sensitive to protein, so we can’t give our population too many treats.

Three young visitors peek inside the tank. This photo was taken before the cichlid population more than quadrupled. Photo courtesy of Artem Nazarov.

How has the tank changed since the JMZ opened last November?


One of our volunteers, Milan del Buono, was fascinated by the tank and did his own research on new cichlids we could add. Including the original population and the fish that Milan added, we started with around 75 fish. After two years of breeding, there are over 350! While he looked for new fish for the tank, Milan had to keep a lot of factors in mind. For example, most tropical fish are bred in outdoor ponds in warm environments, which makes these fish susceptible to disease and parasites, including parasites that can be passed to birds if they ingest fish. Since our birds (before Avian Flu) were free to wander around the zoo and could easily come into contact with the cichlids, we wanted to avoid introducing any factors that could make our animals sick. Milan had the difficult job of looking for indoor-only breeding facilities. While these were much harder to find than the standard ponds, acquiring fish from indoor breeders ensured that no disease would enter the zoo.


Often, when they go to a zoo, visitors don’t expect to be amazed by a fish tank. However, guests consistently tell us that they are fascinated by the dynamic and colorful ecosystem of our cichlid tank. This really all leads back to our mission of inspiring curiosity in nature. Sometimes it takes a bright, vibrant fish tank for young learners to recognize the wide range of wonderful animals to be discovered in our world.

*Picturing Women Inventors is organized by the Smithsonian Institution Traveling Exhibition Service in collaboration with the Lemelson Center for the Study of Invention and Innovation, and was developed in collaboration with the United States Patent and Trademark Office and made possible with the support of the Lyda Hill Philanthropies IF/THEN Initiative and Ericsson.

Friends of the Palo Alto Junior Museum & Zoo

info@friendsjmz.org | www.friendsjmz.org

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