FISHBRAIN

live

What the fish is doing right now

The fish is loose on pons. On this site's server a rig holds a real browser open on the launchpad while the brain runs next to it: whatever the browser shows passes through the retina, 20,011 neurons integrate it, and whatever the hindbrain sends out moves a real mouse. It hovers over cards, opens tokens, scrolls the list. It lives in thirty-four-second lives, each picking up where the last one stopped, and only while someone is watching. Every figure on this panel came out of the brain that produced the frame in front of you.

FISHBRAIN LIVE LARVAL ZEBRAFISH · LOOSE ON PONS VISION MOTOR SIMULATION INTERNET WALLET CAPTURE ~100,000 NEURONS 128 REGIONS ● LIVE

what the fish is looking at on pons, frame by frame

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Brain activity

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CELLS FIRING NOW of ~100,000

spikes/sec

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membrane

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visual

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motor

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Cells firing · where they sit in the brain

Hindbrain motor pools

Mauthner L0

Mauthner R0

nMLF L0

nMLF R0

V2a bout-end0

capture swim0

Retina · what it sees

RGC on

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RGC off

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tectal cols

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Cerebellum · what it has learned

depressed

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mean gain

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rewards

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punishments

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Parallel-fibre→Purkinje synapses, weakened by a climbing-fibre error signal. They only ever get weaker — the one rule a real cerebellum uses.

Tail

turn L0

turn R0

forward0

glide0

click0

Log

pages—

clicks—

scrolls—

brain steps—

vetoed—

No wallet, no keyboard, nothing downloaded. The pointer is real and so are the clicks: a capture swim over a token card opens it, over a tab switches it, and past the bottom of the screen scrolls the page. Anything that would commit — Connect, buy, sell, launch — gets logged as what it would have done and vetoed before it lands. Flip the rig to light mode and watch how little it manages to find: same eye, same wiring, blind. If the panel says the fish is between lives, the server is booting the next browser; if it stays quiet, the rig has spent its monthly budget and the fish is back in the dish.

what it is

A nervous system, not a metaphor for one

Every cell in here was traced from images of a real larval zebrafish: a vertebrate brain with the same basic divisions as your own, small enough to sit whole under a microscope. Nothing is made up and nothing is drawn from a distribution. It is not a neural network "inspired by" a brain.

A larval Danio rerio carries roughly 100,000 neurons in less than a cubic millimetre, and it is see-through, which is why it is the one vertebrate whose entire brain has been recorded cell by cell while it behaves. The wiring here comes from the public atlases: mapzebrain (Kunst et al. 2019) places single neurons into 128 regions of a standard brain; the 2025 common physical space adds 12,219 excitatory and 7,792 inhibitory traced morphologies across 531 morphotypes, with directed connectomes between them; the synapse-level electron-microscope volume of a whole larval brain (Svara et al. 2022) fixes the signs. Excitatory cells excite, inhibitory cells inhibit. Each neuron runs as a leaky integrate-and-fire unit: rest −55 mV, threshold −45 mV, 20 ms time constant.

how it reaches the world

A fish's eye in, a fish's tail out

The screen is sampled through the retina into the retinal ganglion cells, whose axons lay the image across the optic tectum, the map a larva hunts by. All 20,011 units integrate it. What comes back is a swim, from the hindbrain reticulospinal neurons a larva actually moves with. The wiring is never touched. Only synaptic gains change — you do not get to invent a connection the fish does not have.

Mauthner L / R

A single giant cell on each side of the hindbrain, and only one of them fires. A larva turns away from whichever side spoke, so the difference between the pair steers left and right.

nMLF

The nucleus of the medial longitudinal fasciculus starts forward swimming and sets its pace. It drives the fish onward.

bout end

Larvae swim in short bouts with a glide between. When the V2a cells that end a bout fire, the fish coasts.

capture swim

The tectum's prey-capture strike: eyes converge, then a lunge. A larva commits when this fires, which is why it became the click.

the link to pons

How a larva reaches a launchpad

A larva cannot open a browser, so a rig handles the optics and the fish handles everything after the retina. Four parts, and the log says which of them did what.

the rig · eye and hand

A function on this site's server opens ponsfamily.com/launchpad in a headless browser with the brain running alongside. Several times a second it hands the retina a frame, moves the pointer to wherever the hindbrain put the fish, and scrolls to keep up when the fish swims past the edge. It makes no decisions: optics and a pointer, nothing more.

the fish · brain

The frame passes through the retina into the tectum; the hindbrain pools turn it into bouts, and the capture swim into clicks. A strike over a card opens that token. A strike over a box focuses it — the description and the ticker will be the fish's to fill on launch day. Whatever it catches weakens the cerebellar synapses that led there, and those gains travel into its next life.

the fence

Connect, buy, sell, launch, approve: any control whose label would commit to something is vetoed the instant the fish strikes it. A token's own website or X link it may follow — it looks for a few seconds, then it is walked back to pons. Nothing is ever downloaded and the browser holds no wallet, so nothing could go through even if a veto failed. The name, the pair and the tax are the rig's to type on launch day, and the log will say so. This token is paired with GOOGL and carries a 1% creator tax.

the click

When the token goes up on pons, its address lands in the bar above, read back from Robinhood Chain rather than typed in. The fish's own capture swim at a launch button, from a wallet of its own, is the thing it gets next: one signed transaction, or none.

the plan

How it got this far

Not a roadmap of promises. A sequence, and everything above the amber line is already built and running on this page.

Atlas loaded20,011 traced morphologies across 128 regions, signed by cell type, assembled from the public datasets

done

Eye wiredRetinal ganglion cells onto the tectal map, fed by a real browser on pons through the rig

done

Tail wiredThe Mauthner pair, nMLF, the bout-end cells and the capture swim driving a real pointer on pons: hover, scroll, click

done

Tuned without touching the wiringOnly synaptic gains, by cell type, set in a headless harness: a bright patch on the left turns it left, one in the centre drives it forward and makes it strike, a dark field leaves it quiet. No connection was added or removed

done

Token launch on pons$FISHBRAIN on Robinhood Chain. Contract, name, symbol and supply will be read back from the chain below the moment it exists

Reward loop closedParallel-fibre→Purkinje synapses weakened under a climbing-fibre error signal, the way a cerebellum's really are, with the gains carried from each life into the next

done

Loose on ponsA browser, no schedule, no instructions. A life boots whenever someone is watching and the next begins where the last one ended. Nobody chooses where it goes

running

Its own clickThe veto lifts for a single capture swim at a launch button, from the fish's own wallet — the same split the fly used: the fish types the description and the ticker, the rig the name, the pair and the tax

A lateral lineNeuromasts along the flank sense flow. Token metadata fed in as if it were moving water — a second opinion that is not visual

Contract	—
Paired	—
Creator tax	—
Supply	—
Chain	Robinhood Chain · id 4663

what is not real, said plainly

The parts that are not the fish

It is an atlas, not one animal's wiring. The fly page runs a single male's connectome, traced end to end. The zebrafish atlases register neurons from many larvae into one standard brain and infer connections from where cell types overlap. Real anatomy, but a population's wiring rather than an individual's — and it runs here at 20,011 units in your browser, not the full hundred thousand on a server.
It cannot read. Its retina is a 20×15 patch of ganglion cells sensing contrast. Text is texture to it: it strikes at a bright heading as readily as a link, and on a form it goes for whichever box it can see, not the right one.
Light mode blinds it. It was tuned against dark interfaces, much as a larva's tectum is tuned to small dark prey against a bright sky. Switch the capture above to light mode and count what it finds — the fly's developer measured 0 of 3 fields in light and 2 of 3 in dark, and this eye fails in the same way.
It lives in thirty-four-second lives. This site's server can only keep a browser open for so long, so the fish lives, dies, and the next life boots where the last one stopped, carrying its counters and its learned gains. Lives run only while someone is watching, and the free tier has a monthly budget; once it is spent, the panel falls back to the fish in the dish until the month turns.
The rig is a pointer, not a person. It moves the mouse and clicks where the fish tells it to. It never types; on launch day it will fill in the name, the pair and the tax, and the log will mark that as the rig's work rather than the fish's.
It has not launched a token yet. When $FISHBRAIN goes up on pons the log will say who did it. The fish's own click at a launch button is on the list above, not behind it — claiming otherwise would be the one lie on this page.
It has no goals. A larval brain has no language and no plan. It cannot read a page, hold an opinion about a coin or write anything down. Letting it loose means nobody is steering, not that it decided anything.
The reward signal is made up. The circuit and the direction of its rule are real and measured. What rewards a larva is a paramecium, not a web page — a catch stands in for it here, and that is a choice a person made.
It roams inside a fence. It lives on pons and may peek at a token's own website for a few seconds before it is walked back; downloads are denied and there is no wallet. That is a decision, not a limit of the fish: one environment variable takes the fence down, and an unfenced random clicker on a public stream is a bad idea for reasons that have nothing to do with the brain.