Once again, I am Cavity Angel, a man who is trying to become a little god of the Mini-Earth world.
It has been a long time since I last updated my original Japanese blog.
To conclude, this is the current situation.
I mainly used plum wine bottles to create an airtight aquarium, and over the course of several years, I succeeded in generating a succession of shrimp and shellfish.
From there, it was clear what I should aim for as the next step.
I want to succeed in generating a succession of vertebrates, I mean, I want to succeed in it of fish!
However, it was clear that the road ahead would not be easy.
When I checked at the time, I found that even the Mini-Earth at the Nagoya City Science Museum had not succeeded in achieving a generational change based on the "grandchild standard" of platys.
However, I predicted (with quite confidence) that the condition necessary for "generational change in fish" was surprisingly simple.
That was the "size of the aquarium."
If the aquarium was large, it would be possible to grow a lot of aquatic plants that produce oxygen and purify the water, and it would also be possible to easily grow a lot of daphnia, amphipods, and baby shrimp that could serve as food for fish.
However, if the "fish generation change" was not successful in the 100-liter tank at Nagoya City Science Museum, how big would it have to be to ensure success?
Incidentally, 100 liters of water weighs 100 kilograms.
Considering the weight of the tank itself (the larger the tank, the thicker the walls are to withstand the water pressure, and the heavier it becomes) and the weight of the soil, it would be around 120 to 150 kilograms.
So I ordered a 200-liter, airtight tank from an acrylic tank maker.
But then, I had a thought.
Is the apartment floor okay?
Well, surely putting a tall bookshelf and lining it with books until it's packed to the brim is acceptable within the realm of normal living, right?
Or so I thought.
It should be reasonable to assume that the floor would be able to withstand the total weight and pressure of the books in that kind of study environment.
However, the shape of the tank at that time was long and narrow, and the pressure on the floor could exceed that of even that kind of study environment.
In addition, I couldn't help but wonder if it was too wishful thinking to think that something that didn't work in 100 liters would definitely work in 200 liters.
In the previous Mini-Earth, the amount of water that a small killifish could barely survive in was 8 liters.
For shrimp, it was probably about 10 shrimp.
Obviously, for "generational change of fish," it is necessary not only to keep them alive, but also to grow them to a size where they can reproduce properly.
In addition, in an extreme environment like the Mini-Earth, the eating of eggs and larvae by parent fish becomes a serious problem.
If possible, it would be better to use "ovoviviparous" fish (which lay fry instead of eggs) like platies and guppies.
This should dramatically increase the survival rate of the fry.
However, they are one size larger than killifish.
For one guppy to grow from fry to adult, the amount of shrimp that serves as food is 100 shrimp, 10 times the amount in the plum wine bottle experiment.
The amount of water is also proportional to 80 liters, so we assumed that this value was close to the answer.
Furthermore, if we use the "grandchild standard" as a criterion for the success or failure of "generational change," we decided to take into consideration the adverse effects of inbreeding.
Moreover, even if we started with one pair, one male and one female, the accidental death of either one would end the experiment in failure.
Can't we start with at least five pairs?
However, several hundred liters of water are needed to do this, and at this point, rather than worrying about the floor, I can't get into the room!
And so, I, the tooth decay angel, inevitably came to the following conclusion.
I have no choice but to build a house.
And then this happened.
This aquarium stand is made by raising up the concrete blocks that are the foundation of the house, and is extremely durable.
It boasts such durability that it may even withstand an atomic bomb dropped nearby, let alone a major earthquake in the Nankai Trough.
Once upon a time, the grandfather took out a loan with no prospect of becoming a grandmother, and with the endless darkness beyond, where he would finish paying it off at 77 years old, he thought, "Oh oh!
Let's dream!" and took out a loan.
And they lived happily ever after.
Today (2023/09/30), the experiment begins!
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