Strange plants/creatures (?) in my tank (again)

[borracho]

So, I have yet another strange set of creatures or plants in my aquarium. I couldn't find any info about these on the Internet this time. It's very small, so I can't take a picture of it, but I drew one instead on my computer.

There are a bunch of these hanging at the bottom of a plastic container I have for the fry in my fish tank. They are growing in size and numbers! Does anyone have any idea?? They are perhaps less than 1mm in diameter and look like jelly fish on a stick. Maybe some kind of algae?

 

[OrangeCones]

Hydra are capable of eating fry.


Hydra and Moss Animals

 

[borracho]

Are you sure? Hydras don't looks like my picture in the 1st post. The tentacles/hairs are very fine, short, and many in number. It looks almost like a ball if it wasn't for the water movement. Also, they seem to be anchors on the plastic container like flowers.

Anyway, should I wipe it off?

 

[Lotus]

I think they're probably hydras, too. Hydras are a form of jellyfish.

You can kill them with a syringe and hydrogen peroxide.

 

[Doomhed]

those are freshwater hydras. once they get bigger they can eat your fry.

 

[borracho]

I've looked at pictures of freshwater hydras, and they have only a few tentacles. These things I have in my tank, they have a couple of dozens of tentacles on each stem. I wiped them out with paper towel, but they reappeared in another spot, on a plastic surface again.

 

[jamiejay09]

maybe its a type of algae/fungi but it does look like hydras...

 

[OrangeCones]

Are you sure? Hydras don't looks like my picture in the 1st post. The tentacles/hairs are very fine, short, and many in number. It looks almost like a ball if it wasn't for the water movement. Also, they seem to be anchors on the plastic container like flowers.

Anyway, should I wipe it off?

They can change their shape. They can anchor themselves by their base and extend their tenacles when looking for food. They can also swim in the water to look for a good spot to find prey. Look at this website for the shapes they can assume:

Hydra: Versatile Green Predator

Adult fish are not in danger with them, but young fry can be snared/killed by them. You can kill them with peroxide or stop feeding your fish for several days. Like so many pests in an aquarium, its a sign of overfeeding most likely, and/or the need for more frequent water changes/gravel vacs.