Wednesday 2 December 2015

Orbicular Batfish

Image: dachalan
Platax orbicularis
The Orbicular Batfish. A dead leaf mimic so expert, so elite, so dead leafy, that they... thought it was a bat? Hmmmm... Something fishy's going on here. Batfishy.

I mean, just look at this guy! Look at the dead leaf shape and the dead leaf colours. This so-called Batfish is swathed head to fin in the dead leaf uniform. Not only that, they even move like a dead leaf!

Video: willgods

And that means lounging on their side in a most unfishlike manner and mostly not swimming anywhere at all. It's lethargy in the face of danger!

This Sunday morning defence strategy seems to work very well for them. They have a vast, coastal distribution which ranges from East Africa to southern Japan, down to northern Australia and out to French Polynesia, which is half way to Hawaii.

And then they grow up.

Image: Derek Keats
Yup! Only the youngsters are leaf mimics. Adults look very different. Much more... Orbicular. The word means round or disc-shaped and indeed they're also known as Round or Circular Batfish. They're a completely different kind of so-called "batfish" from the likes of the Rosy-lipped Batfish, and belong to a family called Ephippidae, the Spadefish.

Adults reach over 30 cm (a foot) long and look like huge spades that escaped a giant's playing card. The biggest individuals can reach as much as 50 cm (20 in) long. I guess the other Spadefish call them "Ace". We on the other hand are calling a spade a spade. No, wait... we're calling a leaf a bat, a bat a spade and a spade a fish. We have such nimble minds!

Video: liquidguru
May include actual leaves

Juveniles like to hang out in shallow water and may even live in brackish mangroves where nearby trees provide lots of dead leaves to hang around and aspire to be.

Once they reach about 20 cm (8 in) long it's time to don their serious-suit and move out into deeper, more open waters to live like an adult. Until then, it's all about the leaf life.


TexWisGirl said...

awww. the little guys are cute!

Joseph JG said...

It's lovely seeing them just hanging out like that!