Once I got a snail in my fish tank I noticed that the snails started to surf at the surface of my fish tank. I quickly realized they didn’t swim but rather floated. Shouldn’t it be that a snail could swim while living underwater while other animals do?
Snails do not swim. They float by closing their shell and trap some air inside their shell. That makes the air float to the top of the fish tank and the snail with it. Why the snail floats to the top is to breathe or to move quickly.
Not all snails are floating to the surface though. There are also different reasons for a snail wanting to float to the surface.
Why Do Snails Float?
Snails float to the surface mainly to be able to breathe. Another reason for a snail to float to the top of the fish tank is that it gets scared. It could also be that the water parameters are not good enough which makes the snail float to the top of the tank.
The snails that are floating to the top are Apple snails and Ramshorn snails. These snails close their shell which makes a small amount of air get trapped inside the shell.
This makes the snail more buoyant and makes them float to the top of the aquarium. The air they trap inside their shell is the air dissolved into the water.
If there is too much air inside the water, the air could get trapped underneath the shall and makes the snail float.
How Do Snails Breathe?
There are different ways for a snail to be able to breathe according to trained zoologist Luis Villazon as he answered this question in this article at science focus. Some snails have developed lungs and need air to be able to get their oxygen needed. Other snails have gills, as fish do to filter the water to get to the oxygen dissolved into it.
The snails having gills could also have a snorkel to get some air from the surface without floating.
Most snails having gills only have one gill according to Villazon.
The snails that have developed lungs did it when moving from the water onto the land. Gills are to no need on land. They kept their lung while moving back to the water, thus having to go up to breathe.
What Scares Snails?
What scares snails are if any other inhabitants are threatening to eat it. Bad water parameters are also threatening the snail’s lives. Lack of food is the third reason a snail could be scared.
So, in short, anything threatening the snail’s life scares it. While scared the snail could float to the surface to move away from the danger.
A snail is not known for moving fast. A lot quicker way to move for a snail living underwater is to use the water to move.
By making yourself more buoyant you could use the water streams to get far away from the danger into more safe territory.
Now, in an aquarium the snail will not get far, it will rather just move around at the surface ending in the same place as it was before. But it’s an instinct causing the snail to react that way.
If it’s a fish threatening the snail, it will move away from the fish quickly by floating to the top and let the current take it away.
If it’s bad water threatening the snail it uses the current to get to another part of the lake or ocean where the water quality is better.
The main water parameters threatening the snail are pH and the calcium content in the water. The pH is corroding the shell of the snail, killing it, if it’s too low. The calcium is needed for the snail to be able to build its protective shell up.
If there’s no food the snail will move to another part of their living place to find it. The most energy-efficient way of moving is by floating.
However, this makes the snail very exposed and vulnerable. The snail also has no control of where they are going when they just go with the flow.
That’s why they don’t move like that all the time. It’s too big of a risk if nothing is threatening the snail.
Snails That Are Not Floating
Not all snails are floating to get air or if scared. These snails have a gill which makes them able to breathe while staying underwater. The gill works just as the gills on a fish do. It filters the water to extract the oxygen that they need.
Two very common snails to keep and are not needing to breathe air are the Malaysian Trumpet Snail and the Elephant Snail.
These snails are most of the time in the substrate and don’t move far away from the substrate. Inside the substrate, they are protected from the dangers of other animals. They could move underneath the substrate at their own pace and there is a lot of food for them falling in between the spaces in the substrate.
A downside with this approach as these snails are taking is that they are more vulnerable to disadvantageous water parameters. They don’t move quickly enough to escape the bad water.
Now in an aquarium, it doesn’t matter. They cannot escape either way.
If you see these snails float, there is a problem in your aquarium!
You probably have too strong a current which makes air bubbles getting trapped underneath these snail shells and makes them float. If that’s the case, lower the power of the air pump. The risk of a floating elephant snail is that it will get damaged or getting problems with its breathing organ while breathing air.
If you see any snail float, it could be that it’s dead. When a snail dies the shell will be left empty and it could be an air bubble trapped inside the shell making the shell float. Look at the opening of the shell to see if there are any snail in there of it the opening of the shell is closed.
If it’s closed or if there is a snail in there, it’s a living snail.