Wacky Glass Walker

This is the last of the creatures found in Calvin's fish tank, and it reminded us of Wacky Wall Walkers. This is a ciliate that uses it cilia to walk along the top of the glass. Did it evolve this trait specifically for life in a fish bowl?

A quick google search on "ciliate walking on glass" came up with hypotrich, which this appears to be. The legs with which it walks are actually bundled cilia called cirri. What did people do before google? (spend hours in the library, I guess)

Another Rotifer

Here's another rotifer from the scum in Calvin's fish tank, along with his friend the worm. The video below the picture shows the two of them in action. You can see the rotifer mouth sweeping in food, the jaws chomping it up, and the toes wagging like the tail of a happy puppy.






Why are there so many rotifers (three found so far) in this tank? I read that rotifers are added to fish tanks because they eat up debris and keep it clean. Were these added to the pet store fish tanks? Have they continued to propagate and survived the multiple tank cleanings and water changings?

Another Paramecium

Here's another creature found in the scum of Calvin's fish tank--it's quite a zoo in there. I believe this one's a paramecium based on the cilia it swims about with and the contractile vacuoles which it uses to pump out excess water. The video is taken at 100x and you can see smaller bacteria swimming around it, apparently unaware that the paramecium feeds on their kind.

Rotifer Jaws in Action

Here's another rotifer found in the scum of Calvin's fish tank (taken at 400x). At the beginning, we see the rotifer just swimming around looking for food. We then jump to a clip of it eating. You can see the cilia at the mouth moving around to sweep particles into the mouth, and then you can see the jaws chomping it up! The jaws are in the middle of the animal, and look a bit like the mouth of a sabre-tooth cat.

Brown Oozy Worm

Here's another one of Harold's friends. (Harold is Calvin's fish, and we found lots of creatures living in the scum of his tank.)

This is some kind of brown oozy worm. Is it one gigantic cell (for a microbe) or is it a multi-cellular animal? Maybe we should ask Harold.

Vacuum on a Stalk

We looked at some green and white scum in Calvin's fish tank and we found that Calvin's fish, Harold, has lots of friends.

Below is a creature that appears to be a big vacuum mouth that sucks up particles. I don't know why it contracts violently all the time. Is that how it swallows its food?



Update: This appears to be a type of rotifer. These are multicellular animals with a mouth (called a corona, which makes me thirsty), primitive jaws (called trophi) and a stomach. They also have a foot and toes, which are sometimes attached to plants, as the example above appears to be.

Update #2:  It's a Vorticella. Thanks Mr. Comments!