Findings were published in the journal Scientific Reports.
Researchers from Newcastle University in the UK discovered that clownfish have the ability to adjust their growth depending on the environment surrounding them.
Through lab experiments that paired clownfish with varying sized anemones, scientists found that on every occasion the fish who were placed on larger anemones grew faster and bigger than those on smaller ones.
The correlation between sizes, they believe, is evidence that vertebrate growth plasticity is related to a mutualistic interaction.
While it’s not known exactly how the clownfish can do this, Lead author and Lecturer in Tropical Marine Biology Dr Theresa Reuger has a few ideas on why.
“Anemones are important for the fish because they provide protection from predators and the larger the anemone, the more space the fish has to move around and feed while still being save,” she said.
“If the fish would get too big for the anemone it is on, it might not get enough food or be safe. At the same time the fish wants to be as big as possible to be able to produce lots of offspring.”
Clownfish on average are 10cm long and found mainly in coral reefs off the Australian, Southeast Asian and Japanese coasts.
Anemones offer lots of protection to the clownfish, because anything that tries to get in is stung by the organisms tentacles, however clownfish are immune to this.
According to Dr Reuger, the next phase of research will be focused on learning what “mechanism” in the clownfish gives them this incredible growth ability.
“The next step will be to disentangle the mechanism, what makes the fish decide how large it needs to be.
“Through our experiment we already know it’s not food availability (all fish got the same amount of food) and it is not space availability alone (the fish did not show the same plasticity when they were on silicone anemones), so it seems to be something about the mutualistic partner itself.”
