Mandarin Goby emits something

Yas · May 27, 2018

Hi guys,

I keep a Mandarin Goby for 5 to 6 months now, and it emits something white from his back. It's not when he is in danger or something. It seems he emits it for no reason. I had a luck to shoot a video. Have a look.

Does anyone know what it is and what for?

Thanks!

Yas

SashimiTurtle · May 27, 2018

Looks like he sucked up a mouthful of sand and blew it out his gills.

Skep18 · May 27, 2018

+1 for debris through gills.

Yas · May 27, 2018

Ah, looks like it is sand indeed! I've seen a goby that emits sand from its gills, but this one does it from his back! Amazing!

I initially thought it was a kind of poizon or something to evade predator. But there was no predator around it. So it should be sand. Thank you!

Yas · May 27, 2018

Skep18 said:
+1 for debris through gills.

Through gills? I've seen it a couple of times and it looks like it comes out of its back like a whale. I may be wrong though.

mort · May 27, 2018

Yas said:
Through gills? I've seen it a couple of times and it looks like it comes out of its back like a whale. I may be wrong though.

It looks slightly wrong because the pectorals are pushing a strong current of water upwards and the debris is therefore pushed up through the top of the gills rather than it just slowly coming out.