# Daphnia? Good sign or bad sign?



## wastewater (Apr 5, 2010)

Copepods {cyclops} maybe? Have not found them to be harmful from my experiences... but never say never... I guess they could 'possibly' eat shrimp larvae.


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## sayurasem (Jun 17, 2011)

Do they move in a jerky way? Maybe it's copepods, they look like small round thing with two little antenna. And yes copepods are one of the sign of good water parameter.


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## laqu (Oct 17, 2012)

fish think they are yummy...


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## lostraindrop (Jan 16, 2012)

I thought they were copepods too, but I dont think they are. I see copepods in my tank that have two antennas and a tail (that look like copepods when I google it).... but these round ones look really round and have very short hair-like things on one side (that you can barely see). And there so much more of these than copepods that I see. I'm going to take a video and upload so you can see. Is Daphnia a good sign of healthy aquarium, just like copepods?


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## lostraindrop (Jan 16, 2012)

Heres a video of it... you can see the small copepods in the glass and then you can seee the round daphnia(is it?) swimming around.

http://youtu.be/KB1Ieizt2Q0


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## magicmagni (Nov 7, 2003)

I don't know what they are, but I must say your tank looks really nice for a tank that never gets any water changes! If these little buggers bother you get a schooling fish like green neon tetras or whatever you prefer and they will take care of them in no time!


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## wastewater (Apr 5, 2010)

Good video aid pertaining to your questions. I can't provide a 'definite' answer from viewing your video, hard to say with certainty. Put under magnification would probably reveal some definite answers. Maybe someone else could chime with a higher degree of certainty. I do think you are on the right track though... with your reference of size. Sayurasem mentioned copepods with 'jerky movements'. Daphnia and copepods both make those type of movements. 

Daphnia are considered good water quality indicators by water professionals (Daphnia Magna are used often in a bioassay to monitor water quality). As to copepods: I've never encountered any problems with small populations established within my tanks. This is just an opinion (for what it is worth & taken with a grain of salt per se) - I think that overfeeding and water quality deterioration factor into large populations of copepods forming in an aquarium.


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## rollinghills (Sep 19, 2011)

Oh nice I want some in my tank.:icon_mrgr


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## OldMike (Sep 7, 2009)

Could be scuds.


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## VisionQuest28 (Apr 18, 2007)

whatever they are, I can say with ALMOST certainty they are harmless, and more than likely beneficial. Amphipods, copepods, daphnia, etc all eat decaying plant matter, detritus, un eaten food and algae. There are a few exceptions to that, and i think they all come in the form of fish parasites. But i think it highly unlikely that you would see them in such a large number if they were parasites.

That being said, I would think that its possible that having such a high number of them is an indicator of excess nutrients in the water...uneaten food or decaying plant matter. Or could just be that there are no fish in there eating them. But me personally....i think your tank looks great, and i am always a fan of higher biodiversity in an aquarium. The more things living in harmony together in an aquarium, usually the more stable it is.

Also, at this point, its not really ammonia you need to worry about. With all those plants, and only one fish, you probably wont ever see ammonia register on a test again. But without doing any water changes its nitrates that you may need to worry about. Nitrates can become harmful. I certainly am like you though, I do much less water changes than i should, and seem to get away with it just fine.


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## lostraindrop (Jan 16, 2012)

Awesome! Thanks Vision and everyone else for the input! I will start watching my nitrates.


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## mistergreen (Dec 9, 2006)

seed shrimp
http://en.wikipedia.org/wiki/Ostracod

it's a healthy tank with no predators like fish.


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