Freshwater Giant Trevally

James Clain · October 22, 2020

After a little bit of research about the freshwater capabilities of Trevs especially Giant Trevally I came across something incredibly interesting. Giant Trevally are primarily a saltwater fish. However the young ones growing up in the estuaries are very highly adapted at tolerating freshwater.

Lake Taal in the phillipines is home to the only true freshwater GT. Lake Taal prior to around 1754 was a saltwater lagoon connected to the ocean but after a serious eruption from the Taal volcano in 1754 the lake was sealed and gradually became fresh. The saltwater fish, the GT and some other saltwater sardines survived and adapted to become a full freshwater species. The GT in the lagoon are known as Maliputo and are well known as a great table fish and are subsequently have been overfished in the region.

Nowadays the lagoon is connected to the sea, while the Lake still remains fresh the GT have 'swapped directions' and now currently swim to the salt estuarine waters to breed and then return upstream. Similar to Australian Bass.

This is not an abnormality, although I do believe the Maliputo GT are now a specific subspecies as their breeding pattern has changed and maximum size decreased it is still well documented and studied that juvenile GT can survive in saltwater as dilute as >0.05% and there is actually a market for GT sold as freshwater tank fish along with bigeye Trevally which to my knowledge are even better at withstanding the fresh. The sea is on average 3% salt and maximum salt percentage in water is 40%. I believe there is a landlocked lake on the Gold Coast with GT and Bigeye in it?? I really love GT they are such a mysterious fish. As though as nails with fighting power comparable to no other fish.

Check out this video of GT in a koi carp pond -

Here are some sources I used to prove that this is actually a legit thing. "Maliputo, the full freshwater Giant Trevally"

https://repository.seafdec.org.ph/handle/10862/2792

https://themissionflymag.com/2018/10/08/the-maliputo/

https://www.oceanhunter.co.nz/NEED+TO+KNOW/Species+Identification/giant+trevally.html

https://animalscene.ph/2017/11/27/secrets-of-the-maliputo-talakitok/

https://thewebsiteofeverything.com/animals/fish/Perciformes/Carangidae/Caranx-ignobilis