Human-Yeerk Peace Alliance

The best setup for your yeerk colony is similar to that of an aquatic turtle*, with a full bio-filtration system tweaked to compensate for the preferred sludgy nature of the liquid, a water oxygenator, a Kandrona/heat lamp combo, and a number of interesting decor objects for exploration via sonar for enrichment and play. Your population should never increase beyond one yeerk per gallon to prevent over-crowding. When upgrading your tank size, be wary of introducing new yeerks to your colony, as extra space in a healthy environment can trigger spawning among colony mates.

If you notice some of your yeerks have spawned, remove as many of the grubs as you can find with a fine net and place them in an incubation setup. This is actually easier than it seems since grubs have slightly different nutrient and temperature needs compared to adults, and in an artificial set up, they tend to stay at the surface of the water, closer to the heat and light. There can be as many as 800 grubs in an average batch! The highest count recorded was 947, with one instance of twinning (two yeerks forming from a single grub). Grubs are tiny don’t need as much space as adults (about 100 grubs per gallon is ideal), but they will grow quickly and will need a permanent setup in as little as two months.

Yeerks enjoy staying with their spawn-mates long term, as they would in their natural habitat, and a single batch of grubs is actually a very stable colony! But we understand not everyone can keep several hundred yeerks together in adulthood and the batch will need to be split up for rehoming. This is best done while still in grub stage, as their senses are much more limited, and bonding between batchmates only begins upon entering the second stage of maturity. It’s not recommended to separate colony members past this stage.

With proper care, you can maintain a happy healthy colony of these fun little guys indefinitely! They are excellent friends and companions!

Yeerks are not cute little pets you keep in an aquarium. Yeerks are people. Pools are not adequate long-term habitats for them, they are spawning and feeding grounds; a Yeerk’s long-term habitat is inside a brain. Keeping Yeerks without access to body they can move in and use a full sensory suite with is equivalent to keeping humans in solitary confinement, i.e. torture; if you’re managing a Yeerk pool with a permanent unhosted Yeerk population you are a prison warden. They are not your “friends” or “companions”, they are your victims, and if you spent even a second hearing what they have to say you’d know this.

Remember: Everybody needs their alone time and everybody needs a safe, welcoming space to retreat to. This is also true for Yeerks, since they are a gregarious social species who have their own social structure independent of their hosts. A Yeerk Pool should be a communal affair, and letting your Yeerk swim alone would be cruel.

1) The idea that yeerks find a properly maintained pool to be “torture” or “a prison” has been contradicted by literally thousands of first-hand testimony from yeerks themselves. These accounts describe the pool immersion to be comfortable, safe, surrounded by familiar colonymates, and energizing from constant absorbtion of necessary nutrients. In fact, most of the “prison” narratives in earlier care guides were artificially pushed by the very propaganda mentioned above, and has been largely debunked now that many of the authorities that pushed it are no longer in positions of power and influence in the sphere of yeerk enthusiasts.

2) The idea that a host brain is the “natural” habitat of a yeerk is demonstrably false. A yeerk will literally die in a host brain if they don’t return to a pool within 72 hours. It is a temporary experience at best. And while many yeerks enjoy it and choose to maintain an ongoing symbiotic host relationship, it can be an extremely stressful and negative experience for others. Many pool-raised yeerks will try a host out of curiosity, but elect to remain in the pool nonetheless. Yeerks should not be forced to take a host if they don’t want one! It’s not necessary for a satisfactory life and can be debilitating for both yeerk and host if forced. Not to mention that a lot of involuntary hosting was also forced during the time stated above as a result of said propaganda, and I don’t have to get into how absolutely unethical that was as well.

3) This notion pushing that unhosted yeerks are inferior or incomplete is once more pure, obvious propaganda. These are capable sentient beings who lead full lives in their pools, complete with complex social interaction and interpersonal relationships. Purporting that the way they naturally interact is insufficient compared to ours is extremely speciesist and denotes a lack of understanding of the relevant xenobiological research.

4) Just because the pool caretaker may not be able to communicate directly with their yeerks does not mean they are a “prison warden”. Yeerks in a properly maintained colony meet all their social needs with theur colonymates. Again, assuming they need human companionship implies that their own species is somehow inadequate for them. You can see how deeply harmful and isolating that kind thinking is if pushed on them, especially for those who find the host experience unsatisfying. They end up thinking something is wrong with them, when in fact they are completely normal! As long as they are well cared for, many yeerks are content being unaware of their caretaker entirely. Some may curiously interact with you, but don’t be alarmed if most ignore you completely. As I said, they have full and enriching lives already. If your colony is happy, healthy, and stable*, than you’ve done everything you need to for them.

* In the case of yeerks, “stable” refers to a colony that does not increase or decrease in population during the majority of the yeerks’ lifespans, while still having all their space, nutritional, and social needs met. These are also referred to as “full pools”, since in their natural habitat no spawning occurs in a full pool until there is sufficient space (ie when enough of the inhabitants reach the end of their natural lifespans). Conservation efforts rely on maintaining stable colonies, rather than exponentially increasing overall population indefinitely, as research has shown stable colonies to be where yeerks are happiest for the majority of their lifespans. See the cited paper for the relevant research conducted by Dakor-288 and Johanna Brun for more details (Dakor-288/Brun et al. 2018).

And 5), there are established means of communication between caretaker and colony if needed! I can only assume anyone commenting to the contrary has never kept a colony as they seem to unaware of this, but since these are sentient beings who, as of now, are unable to thrive in their actual natural habitat of their home planet, they are heavily protected and you need to be licensed to maintain one. This comes not only with mandated inspections, but also access to resources like symbiotically hosted yeerks who can communicate with your colony on your behalf, and technological developments to allow yeerk sonar pulses to be heard and translated by their caretakers. There are also numerous programs to take in unexpected grub colonies from people who can’t maintain them.

We may use a lot of the same terms, equipment, and language for them as we do for pets because of how similar the act of caring for a colony is, but they are indeed a sentient species undergoing heavy conservation efforts. No one who legally keeps a colony is unaware of this. And while regulation can definitely be improved in terms of quality and accessibility, household colonies have been shown to have an overwhelmingly positive impact on conservation efforts. Please don’t conflate responsible keepers with illegal breeders! And always get your yeerks from a licensed provider!

Citations mentioned:

2018

Dakor-288/Brun, Johanna L., Emilio Veres, and Issun-433/Penelope Carlysle

so this is one of those cases where I forget that my headcanons are not universal, whoops

I don’t think anything that I’m about to say is noncanonical, but I might not be able to reliably provide sources. what I will do is try to explain what I mean, and hopefully make it make sense? okay.

in #29, Cassie talks about how when she’s a Yeerk, she doesn’t actually feel upset at all at being in the Pool in her natural blind state. She’s happy, and contented, and glad to be with her brothers and sisters. This stands in stark contrast to Aftran’s bitter insistence in #19 that it’s inherently unfair for a Yeerk to be sapient and self-aware while being eyeless and senseless, but I think it’s important because Cassie naturally does have the expectation of sensory input beyond echolocation and some tactile sensation. Her mind expects eyes and smell and hearing, and it’s not getting it, and yet there’s none of the body-horror aspects we see in other books of losing aspects of oneself thanks to a particularly powerful morph or doing something natural for the morph but being terrified anyway (ant, termite, mole, Taxxon). When she takes a host - when any Yeerk takes a host, actually - what happens, then, has to be more complicated than just trying to follow one’s instincts to achieve a naturally desired end. They’re not taking hosts to escape the existential horror of having self-awareness but not being able to do anything with it. There’s something more complicated going on here.

What is it?

Well, I’d argue that they’re junkies. They’re sensation and neurotransmitter junkies the same way the Andalites are taste junkies, but on a much more grand scale. They react to hosts like it’s something they’re entitled to, like it’s ridiculous to expect them to go without this, but by my read it’s not because they feel a relief of having an outlet for urges they otherwise can’t explain, it’s because they like the feeling of having a host. They like the sensory input, they like the brain chemicals. And often, it’s not just enough to experience these things fleetingly, they can’t “drink socially”. It’s all or nothing. Esplin is so obsessed with Andalites that he has to have one, and Edriss LARPs the perfect housewife life more eagerly and happily than her job in the Yeerk military. There’s some commentary, I think, about “getting too close” - what does that mean, for an involuntary host and their Yeerk, but addiction to this existence?

- self-hatred and self-disgust of unhosted yeerks seems endemic in yeerk society. They declare themselves the glorious destined masters of the galaxy in one breath and disgusting and helpless when unhosted in another. This duality is explored pretty thoroughly with Aftran, and it seems to be the party line, taught to them from birth. “You are great and powerful with a host, the empire is great and powerful with many hosts. Without them you’re fucking useless.”

- rank is pretty closely married to host access. We see a taxxon controller counsellor and some of the higher ups have what we humans would consider pretty boring or low-status jobs, but on the whole ‘better host = higher rank’ holds pretty firm. Yes, this is what we’d expect in most societies -- power buys privilege, including access to better hosts -- but it’s also a two-way street. It means that having a better host broadcasts to other yeerks that you’re more important. And if you don’t have a host at all? You’re worthless. Nobody important wouldn’t have a host, even though unhosted yeerks can communicate via computers just fine (as seen in The Andalite Chronicles and could still get management and command work done in their natural states).

- host access is artificially restricted via overwork. Yeerks are expected to work literally to the brink of death on every shift, exiting their hosts to feed only when they come close to starvation. Think about that for a second. Yeerks can draw memories from host brains at will and tell their hosts things at any time; there’s no reason for one yeerk to have the same host all the time. A safer method would be to work in teams of 2, taking the host for one day and then having one feeding/rest day. Anything the yeerk needs to know about its partner’s behaviour will be in the memories. It’d mean more trips to the yeerk pool but since there are entrances absolutely everywhere that’s not a problem, and it’d also mean more flexibility in scheduling pool trips -- in an emergency, someone could stretch to 2 or even 3 days.

But yeerks with hosts spend all of their time in a host and the minimum amount of time possible feeding. This is massively unhealthy for every kind of higher animal we know about, including humans, and presumably it is for yeerks, too. But what are they gonna do? Complain? Say they want to spend more time as a gross helpless slug? Sounds like a great way to lose your host to someone more ‘dedicated’.

- the yeerk pool seems to be kept deliberately boring. The natural pools on the homeworld must be bursting with life (natural pools generally are), but every description we see of a pool makes it look boring, uniform, and sterile except for the yeerks. Cassie says that yeerks ‘communicate very little in their natural state’, which can’t possibly be true. If they want to talk, why wouldn’t they talk? Presumably social convention. It’s not done to talk while eating; you eat and you get back to work. Of course yeerks without hosts are going to be bored out of their minds. Of course they’re going to want nothing more than to get a host. Of course they’re going to become addicted to alien sensation, when they don’t get to indulge any of their normal sensations.

Jake: So, Dad, are there any parasites that can live in a person’s brain?

Steve: Yes! Well, it’s not technically a parasite, but if you go swimming in fresh water in Florida in the summer, you are at risk of getting Naegleria fowleri, which is a brain-eating amoeba. It just goes in there and eats your brain. Most patients die within a week.

Jake: Wow, and it gets in through your ear?

Steve: No, don’t be silly. There’s too much stuff between the ear and the brain.

Steve: It goes in through your nose!