Clearly neither of these happens because although these organisms produce enormous numbers of offspring, almost all of them die before adulthood. Connected with this is the fact that the adults in these species often die immediately after mating. For instance, there's a species of bootlace worm which has no way of getting its sex cells out of its body, so it basically explodes with pleasure at the end of its life and the sperm and eggs combine that way. If that kind of thing didn't happen, the adults would still be there using up the resources needed by their progeny, an issue which is also important to us. This is also why female spiders eat their mates after mating and why praying mantises eat theirs - they need the food for their children.
Another thing some species do to spread their genes is to have babies without mating. Greenfly and other aphids, for instance, are born pregnant and give birth at the age of twenty minutes. Stick insects and water fleas are similar. Some species are even exclusively female, such as some skinks and geckos. This means they can reproduce without the problem of finding a mate or having a mate find them. However, this comes with a price: children from virgin births are genetically identical to their parents, so an entire species of individuals born without mating in this way has little genetic variation, with the result that they are vulnerable to extinction because similar threats will kill them all, rather than only some of them as would be the case with more variable species such as our own.
Human beings are not like that. We get together, have small numbers of children together and raise them, investing a lot of time and energy into doing so. These children are all, with the possible exception of identical twins, unique - we do not have clones. Rather than dying immediately after mating or giving birth, we stick around and bring the kids up. In fact, unlike almost every other species, we go so far the other way that we actually stop reproducing long before we get old, possibly so we can raise the grandkids.
Our individuality enables our society to be flexible and adapt to change and we need a huge amount of interaction early in our lives because there are so few of us and otherwise, none of us would survive to have children of our own. With respect to society, this means that we cannot really pursue a strategy of child-rearing which attempts to standardise children's achievements - that would make them more like clones and lead to an inflexible and vulnerable society or mental illness - or raise children in large groups with relatively few adults involved. Therefore, schools of the kind we have now are not educational institutions. That could be OK, provided it's also OK that we will die out soon as a species and our descendants will suffer a lot in the process - i'm serious about that as a viable and acceptable option, though it's not one on which i'm personally keen.
Hence schools are for fish. They are suitable for homogeneous groups where there is no parental care, almost all of whom die in infancy or which are genetically very similar. That does not describe our species and we are therefore risking our extinction to raise children in this way. As a result, we chose to make our children aware of and feel free to opt in or out of school and to change that at any stage.
This is only sort of about fish. It's more about the fact that schools would work as educational institutions if we were a different kind of species, which makes me wonder if somewhere out there in the Galaxy there is in fact such a species, and if so, whether it's quite vulnerable to extinction. I'm a little nervous putting this out there because i know there are a lot of people with a great deal of respect for the educational system and i have a great deal of respect for them in turn. It's also too long, a problem which is getting worse. I will get this sorted.
Back to the aliens. What would it take for there to be a tool-using species which was suitable for school? It would lack parental care as we understand it and the individuals would be genetically very similar, with the result that to succeed, they would either need to have castes like social insects or be multi-talented themselves. I have a feeling this is the same species as the one with the fixed hereditary language. It would also be very similar in some ways to a social insect, and in fact throughout the process of making this video, i've had termites at the front of my mind.
So: it's insect-like in terms of social organisation but not anatomically, and clearly it can't be chordate because chordates are improbable, at least large ones. Well, it could be, but let's not complicate things. Is this species going to get into space? Is it already there? Hold on, let me just get this out of my system: