What are these little critters?

[mchambers]

I was moving some Corydoras (I think CW014) fry today out of their little container into a real aquarium with other fry. I put them in a specimen box and took some pictures and a video, and noticed little things moving around in the water. I've been feeding the fry banana, walter, and micro worms, in addition to golden pearls and decap BBS. Any idea what these things are? They certainly aren't hurting the fry.

 

[chriscoli]

freshwater copepods (Cyclops). I see a female, even.

 

[mchambers]

Wow. I knew you'd know.

Wonder where they came from?

 

[chriscoli]

they're everwhere. I'm surprised they're not eaten yet!

 

[Frank Cowherd]

Yep, easy to identify. Cyclops are fast, so I think fry have a hard time catching them unless they stop right in front of the fry. But eventually the fry get faster or is it more intelligent. Cyclops tend to show up in any old water (tank or culture) so maybe their eggs are coming in with fish food.

 

[mchambers]

I've actually been feeding my fry freeze-dried cyclops. Maybe eggs that survived freeze drying? Or maybe they came in on plants?

 

[chriscoli]

probably came in on the plants, but maybe on the food. I don't know how if they form a cyst and how tough it is.

 

[mchambers]

Well, bless them and the plants they rode in on! I'm always happy with more sources of live food.