What are these swimmy things and should I worry??

[Nells250]

 

[MattW]

Seed shrimp! or Ostracod. I don't think they'd pose a threat to anything in the tank.. more of a snack-sized bite to any fish passing by. Im quite jealous actually, never been able to get anything like that in my tanks

 

[CassCats]

They're ostracods. Aka seed shrimp.

They are harmless and fish may eat them but they're known to pass through the digestive system intact and alive, so aren't necessarily *nutritious* lol

 

[Nells250]

THANKS! I seem to have accidently deleted the text in my post while adding the photos.

MATTW - If I thought they would arrive alive, I'd ship a bunch to you! I don't like the look of them. It bothers me...

 

[AdoraBelle Dearheart]

THANKS! I seem to have accidently deleted the text in my post while adding the photos.

MATTW - If I thought they would arrive alive, I'd ship a bunch to you! I don't like the look of them. It bothers me...

What kind of fish do you have in the tank? Because a couple of mollies would make short work of them!

 

[Colin_T]

If you have Ostracods in the tank, then your water is pretty good. Daphnia are another crustacean that can be used as a canary in a coal mine so to speak. If you have Daphnia swimming around breeding in the aquarium, then the water quality is suitable for fish. If the Daphnia or Ostracods die, check the water quality.

 

[Nells250]

Colin_T = Interesting! They are in the 2 tanks I don't really pay attention to water-wise!!!​

AdoraBelle Dearheart = No fish, just shrimp and my test-plants.​

 

[CassCats]

Just gonna put it out there.

I've got a 250ml jar sitting in my living room window with sand, cyanobacteria, and bladderwort bits and ostracods are in there having a party all the time. Jar was meant to house a plant bulb I wasn't sure of its identity for awhile, and I've been too lazy to deal with it and it took a mind of it's own so I have left it...

But if they're thriving in that cesspool jar, I wouldn't consider their presence to be any indication of tank health.

 

[Nells250]

I was just looking at these things ruining the look of Test Tank #3... then for kicks I looked on Ebay... people SELL these! Hmmmmmmmmmmmmmmmmmmmmmm...

 

[MaloK]

Just gonna put it out there.

I've got a 250ml jar sitting in my living room window with sand, cyanobacteria, and bladderwort bits and ostracods are in there having a party all the time. Jar was meant to house a plant bulb I wasn't sure of its identity for awhile, and I've been too lazy to deal with it and it took a mind of it's own so I have left it...

But if they're thriving in that cesspool jar, I wouldn't consider their presence to be any indication of tank health.

I have some of the "zebra" kind, they are thriving trough a fishless cycle with nitrite off chart, no problems.

 

[AdoraBelle Dearheart]

I was just looking at these things ruining the look of Test Tank #3... then for kicks I looked on Ebay... people SELL these! Hmmmmmmmmmmmmmmmmmmmmmm...

Haha! Yes, side hussle away, girl! Let the tanks help pay for the cost of running them

 

[Nells250]

Haha! Yes, side hussle away, girl! Let the tanks help pay for the cost of running them

I wonder how people count them!!!

 

[Colin_T]

I wonder how people count them!!!

They take a small amount and physically count them out. Then they multiply that into a cup or certain volume and estimate how many. Most places that do this put in more than they state.
eg: You order 2000 Daphnia, but you usually get 2500+.

 

[Nells250]

I figured it was something like that. Just seemed to me like counting sand particles

 

[Seisage]

I have some of the "zebra" kind, they are thriving trough a fishless cycle with nitrite off chart, no problems.

There are zebra ostracods??
Man, aquarists and our obsession with anything black and white striped. They'll make anything a "zebra" these days!