The pelagic animal game

[smellzlikefish]

For the ultimate critter experts

I have a selection of photos taken while blackwater diving. They include various types of larval fishes, squid and other invertebrates that have been identified by leading experts in the field. I'll post a photo and in a few days try to remember to repost with the actual identification and some information on the critter. If this is popular, I may try posting one every week. Let's start!

Name this species:

 

[knotical]

Well, it's pretty clearly a cephalopod.
It appears to have eight arms and no obvious tentacles, so I'd say some sort of octopus.
However, the pictures are labeled "Pelagic Squid" so I'm wrong, and perhaps the tentacles are nascent.

 

[smellzlikefish]

This is Ancistrocheirus lesueurii. Their paralarva (seen here) develop in the epipelagic waters of tropical oceans the world over. Once mature, they will sink to 200-1000 meters down where they will live out the rest of their lives.

 

[smellzlikefish]

Here is the next one. Give it a go!

 

[vincent54]

A baby Oarfish?

 

[knotical]

A baby Oarfish?

That was my first thought, too. But ... ?

This is fun.

 

[smellzlikefish]

Nice try. Not an oarfish.

 

[vincent54]

My last guess would be a baby pearlfish. Im too scared to hang out black water diving, so keep posting!! Cheers

 

[smellzlikefish]

Ding ding! Vincent got it! As carapids mature they lose the head filament (known as a vexillum) and long tail filament. Many species live out their adulthood in the anuses of echinoderms. Many even parasitize their hosts' gonads!

Let's try another one. You will probably be familiar with the adult version of this:

 

[smellzlikefish]

If anyone is still listening, the last one was a yellow tang larva (Zebrasoma flavescens) somewhere around or after day 40. I am told that the pigment sash over its eye is a form of mimicry that looks like a smaller fish pointing up. Nature is weird.