What are Siphonophores?

These fish got they/them pronouns!

Siphonophores are these delightful critters that live beneath the sea.

What's so special about them, you ask? What's special is that a single Siphonophore body is actually made up of a bunch of tiny organisms called Zooids. They are colonial organisms!

These Zooids carry out a whole host of tasks like the organs in a human body. They are so similar to organs in fact that they inspire us to question the very existential question of what an organism even is and where the individual ends and the colony begins and what the difference between organ and organism even is.

They are also generally bioluminescent. They are NOT jellyfish, jellyfish are individual organisms. The insinuation is preposterous.

How Siphonophores Move

2 out of 3 siphonophore types use Nectophores for movement (we'll get into types later).

Nectophores are zooids which are basically tiny rockets which use jet propulsion to push the siphonophore in the water. How cool is that!

Nectophores are arranged at the "head" of the siphonophore, called the Nectosome, and they all may push in different directions.

Let these fine fellows demonstrate

Truly beautiful.

The siphonophores which don't have nectophores have a floatation device called Pneumatophores, and they are carried freely by the waves.

Types of Siphonophore

Siphonophores, or order Siphonophorae, are members of Phylum Cnidaria (the stingy sea creatures like jellyfish).

As I've alluded to above, Siphonophorae is divided into 3 suborders based on the presence of Pneumatophores and Nectophores. These are:

1. Physonectae

  • Pneumatophores
  • Nectophores

2. Calycophorae

  • No Pneumatophores
  • Nectophores

3. Cystonectae

  • Pneumatophores
  • No Nectophores


Marrus orthocanna

These have a bunch of nectophores on their nectosome. The fine fellows you saw swimming above? Those were all Physonects!

They are very mobile and usually swim in the open ocean (the Pelagic zone), though one particular family (my favorite) crawl along the sea floor.

Image By Kevin Raskoff


Muggiaea atlantica

These have very few nectophores, usually only two, which make them look like rocket jets. They can suck up their siphosome (stem) into a sac to reduce drag.

Some of them have an altered chemical composition in their bracts which makes them more buoyant, to counteract the lack of Pneumatophores!

Image By Zachary Hawn


Physalia physalis

They don't have swimming bells so they usually float along the surface, drifting along with the wind or the currents.

Arguably the most famous siphonophore, the Portuguese man o' war, is a Cystonect.

Why I love Siphonophores

Siphonophores are so biologically interesting, both as Cnidarians and as colonial organisms. There is so much to learn about them and we haven't even scratched the surface yet. Siphonophores are very delicate so it's hard to study them so very little information exists on the more niche species.

Thus siphonophores remain a tantalizing look into a lifeform so alien to us, yet they are beautiful critters. You can spend hours being mesmerized by the video of siphonophores swimming (or atleast I have).

This is one of my most favorite videos to look at from time to time:

This is likely the best place to mention that I'm not a marine biologist, or any kind of biologist. I only have a passing interest in biology, but researching about these fascinating creatures have made me learn a lot more about ocean life. Atleast I can throw around big words like Pelagic and Benthic now. But I genuinely believe looking into these critters has done a lot of good for me.

This is the video that first got me into Siphonophores:

Go check it out! It's a far more comprehensive look into Siphonophore biology than I've had the wit to elucidate here.

Also, yes. Siphonophores are the namesake of my website.

My Top Five favorite Siphonophores of All Time

Dishonorable mention: Portuguese man o' war. Overrated. Boo. (don't tell her I said this)

5. Chuniphyes moserae

I realized I had no Calycophorae on the list. I am currently not being held hostage by a colony of malicious Calycophorae and I am not being threatened with any nematocysts (stingers).

But they do genuinely look cool though. Tent lookin' ass.

Image by Alejandro Damian-Serrano (MBARI)

4. Erenna richardi

Also known as the Feather Boa Siphonophore. This one is on here purely for the looks.

I mean look at them! They look ethereal, almost angelic. They look like if the Light Dragon from Zelda was a tad more eldritch.

They look so fluffy but those are just their stingers. Don't try to cuddle one(?), please.

Image by MBARI

3. Bathyphysa conifera

Also known as the "Flying Spaghetti Monster". Yes, like the god!

They're a cystonect but they don't idly float on the surface. Instead they contract and relaxe their siphosome for movement which is really neat!

Image from the Serpent Project Media Archive

2. Apolemia

In 2020, an individual of genus Apolemia was found, in a spiral position, off the shore of Western Australia (pictured here). Its full body is purportedly 119 metres long (exact figures vary wildly but this is a common estimate).

To put that into perspective, that is just a little over 85 metres longer than the longest blue whale ever recorded.

It is commonly known fact that siphonophores are one of the longest creatures alive right now, with the Giant Siphonophore growing up to 50m in length, but this blows that figure out of the water (heh).

Also Apolemia uvaria was nicknamed by New Zealand folk as the Long Stringy Stingy Thingy. I think that's really the most notable thing here.

Image by Schmidt Ocean Institute

1. Dromalia alexandrii

My beloved, the closest thing the sea floor has to a pinata. They look so cute what with the bunch of cute little nectophores and tentilla and I just wanna give them a big hug even if they burrow into my skin and kill me badly.

They belong to the Rhodaliidae family, a kind of Physonect siphonophore that are benthic in nature, i.e. they attach themself to the sea floor by the tentilla instead of roaming the open ocean.

I have so much love for this silly goober. Content in its own patch of the sea floor. Moisturized. Unbothered.

Image by MBARI

My Siphonosona

Yep. This was inevitable. Here it is:

pinkish purple Dromalia siphonophore attached to the sea floor

Of course, it's based on Rhodaliidae, and it's benthic.

I'd love to become a siphonophore. It wouldn't even be me anymore. The egotistical conception of a self would be lost in the sublime collective abstraction.

I would eat fish and bob around nonchalantly.

Other art I made

JonMartin from the Magnus Archives as Siphonophorae

Jon and Martin as siphonophores swimming in a heart shape

Jon is a stereotypical Physonect. Martin is a Woolly siphonophore. Can I make it more obvious?

More links and videos

Casey Dunn's Creature Cast series

The entire playlist is a delight but the "hunting with tentilla" video is a particularly enlightening on how siphonophore nematocysts are very peculiar even among cnidarians.