Excluding the apple snail, four types of snails live happily in the 1-ton Mini-Earth "Biocube": the comon pond snail, the red ram's horn snail, the Japanese river snail, and the freshwater snail .
This is especially true for the comon pond snail, which is often hated as a "snail" in a normal aquarium because it tends to multiply too much, but in the Mini-Earth, the food situation seems to be quite severe and there is no explosive growth.
And when comparing the size of the adult snails, upturned snail(Physa acuta) < red ram's horn (Indoplanorbis exustus)< Japanese river snail(Semisulcospira) < freshwater snail (Sinotaia quadrata histrica), so it is the biggest eater in the snail series and is thought to be difficult to breed.
common pond snail
red ram’s horn
Japanese river snail
freshwater snail
However, the freshwater snail has a special technique that cannot be used by ordinary small snails!
That is filter feeding!
Filter feeding is a technique in which the fish suck in large amounts of water and, as the name suggests, filter out suspended solids (the source of turbidity) with their gills and eat them.
In particular, the freshwater snail makes green water transparent, so it can be assumed that it eats phytoplankton.
When the Mini-Earth experiment began, large numbers of them were released to eliminate the green water in the hopes of using this ability.
This point is extremely important in the Mini-Earth experiment.
In order to make observations, it is absolutely necessary that the walls are not covered in moss, but similarly, observations will not go well if the water itself becomes too dark in color and visibility is poor.
The freshwater snail is also highly capable of removing moss from walls, and as an added bonus, it increases the transparency of the water, making it a god-like existence.
Let's think a little more about this filter feeding.
Even in the world of ordinary aquariums, the freshwater snail has such high specs that it is surprisingly common for it to die early, and it is rumored that it is probably due to starvation caused by a lack of moss.
And speaking of filter feeding, bivalve mollusks such as freshwater clams are the specialists, but freshwater clams are even more difficult to breed over the long term, and breeding them is said to be nearly impossible by not an expart.
freshwater clam
From here on, it's going to be a pretty nerdy story, but I once read somewhere that the plankton that makes up so-called green water is filtered out by bivalve mollusks such as freshwater clams through filter feeding, making the water clear, but it is excreted undigested and does not provide nutrition for the bivalve.
Apparently, the bivalve mollusks get their nutrition from diatoms, not green algae.
So, can the freshwater snails, which are also filter feeders, digest green algae?
Also, isn't it possible that with such large aquatic plants and the addition of large amounts of fallen leaves, diatoms are flourishing, something that doesn't occur much in normal aquariums?
However, depending on the combination of conditions, the filter-feeding behavior of the freshwater snails could mean they compete with bivalves and daphnia!
The freshwater snail is not only a reliable guy, but also a gateway to romantic mystery, making us think about various unsolved problems.
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