The pelagic animal game

[smellzlikefish]

Let's try another one:

 

[Scuba_Jenny]

mahi mahi?

 

[smellzlikefish]

Yup! Mahi (Coryphaena hippurus) are one of the fastest growing fish species out there.

That was easy, try this one:

 

[Scuba_Jenny]

I want to say a file fish, but probably more like a pompano or jack

 

[smellzlikefish]

The extruded gut is the key here, present in neither Carangids nor Monocanthids. Keep trying!

 

[Scuba_Jenny]

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:

View attachment 211146

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.

On a thread on FB, a similar photo was posted and one of the comments was :

that mimicry thing is likely "fake" mimicry, something humans notice that isn't purposeful- usually a fish does NOT want to look like a smaller fish that would attract predators. Note that the silver protects the brain and viscera from UV light, and the opaque cover of the gut prevents luminescence of prey attracting predators. Many larval fishes have black or silver coverings of the cranium and gut, just not stretched out like this.

Interesting... yes, animals are weird.. freaking awesome..

 

[smellzlikefish]

Interesting concept. Evolution does not have a defined "purpose," but instead just kind of stumbles around until something works and gets passed on to the next generation. The mimicry here was actually pointed out by a couple of larval fish experts at the Smithsonian, but the advantages you point out are certainly valid. I'll send your thoughts along and see how they react.

The most recent post was a larval Astronesthes, or snaggletooth, in the family Stomiidae. As an adult, this animal will live in mesopelagic (midwater) and develop a barbel under its chin that acts as a sort of lure.

 

[smellzlikefish]

The last one was a larval Stomiid (dragonfish) in the family Astronesthes (snaggetooths).

This next one is probably one of the most common pelagic animals we see.

 

[Scuba_Jenny]

My first guess would be a giant squid. Or that giant octopus found in the Pacific NW

And that is without hoovering over the image to see the file name and doing a simple google search.

 

[smellzlikefish]

Well that's a rookie mistake on my part! Damn.