View Full Version : What is this?

11th Dec 2005, 08:48 AM
I was taking pictures of the little creatures in my aquarium (hydras, cyclops etc.) and I found this one which I can't recognise. It is the same size as cyclops (0,5-1 millimetres, but I am bad at estimating), it moves like it has legs (sort of walks against the front glass) and sometimes jumps a longer distance, but I haven't seen these swimming, I suppose they are able to swim too.


Does someone recognise it?

And here's a picture of Cyclops to give something to compare it to. This is the same size and taken from the same distance as the first picture of this unidentified zooplankton creature.


11th Dec 2005, 10:16 AM
those are cool and very clear pictures, NICE camera work:D i have seen the first creature in my tank, and it does swim, but i have yet to figure out wat it is either, ive also got these black spider looksing things :shocked: lol they are all about the same size though

12th Dec 2005, 10:45 AM
I really enjoy taking pictures of these little ones. It is fun and challenging.

I just found out, they are Ostracods, seed shrimps, tiny crustaceans. Check out these pictures I found: picture 1 (http://www.landcareresearch.co.nz/research/biodiversity/invertebratesprog/freshwater_invertsCD/images/Ostarcod.jpg), picture 2 (http://www.luciopesce.net/zoologia/daniel1.jpg) and picture 3 (http://www2.una.edu/microaquarium/images/Arthropods/Crustaceans/ostracods/ostraBrightField1cm.jpg). I so need to get a microscope.

12th Dec 2005, 07:52 PM
Hi Satu,
you were faster with the answer of your question yourself than me. I also think that they are Ostracods (in German we call them "Muschelkrebse"). These tiny crustaceans can do pretty well in a tropical tank but they are harmless, so don't worry. In some of my tanks, especially the ones with lots of moss and mulm, I have thousands of them. Most fishes don't eat them, only my betta males are pretty much interested in them. Ostracods are hardy and can survive under most conditions of a normal tropical freshwater tank. So it's hard to get rid of them. I don't care about them anymore, they found a niche in my tanks and they are harmless to my shrimps, snails and fishes.


Jane of Upton
13th Dec 2005, 11:14 PM
Great pictures! Having seen the other group of 3 pictures in your later post, I can now go back to your images and "recognize" the shell outline. Cool!

Thanks for posting the great picts! I've got copepods and other zooplankton, so I'll now be on the lookout for Ostrapods as well.