Copepods

[Blinky]

Noticed something teeny moving on the glass in my 10g shrimp tank today. I counted about twenty little critters, about 1/4 the size of a grain of salt (I can barely see them they're so small). They seem to be sticking to the glass, scooting around in little half circles. They look roughly the shape of a tadpole. I did some Googling, and I'm guessing they're copepods, and harmless. Can anyone shed any more light on the situation?

I know copepods are often a sign of an overfed tank, and that's a possiblity even though I try not to feed too much. My shrimp are filter feeders. I feed them a small amount twice a day, crushing their food so it floats suspended in the water for them to 'catch', and it therefore ends up all over the tank. There's never any visible excess food, and the tank is full of red ramshorns to clean up food and plants to soak up nutrients, but it's possible I'm accidentally overfeeding.

On very close inspection, it appears they have a forked tail and little antennae, they're definitely copepods. With the funny way they dance around, they're actually kinda cute, for a pest :)

[Tuolumne]

You going to name them all? :p

Sounds neat though. I like when interesting, non-harmful things like that happen. Will your fish eat them? (Oh, wait, is this in your shrimp only tank?) Looks like they've got roommates then, hehe... :D

Maybe you can suck some up in a syringe or turkey baster to feed to your fishies? Unless you'd like to keep them contained to one tank. I don't know anything about them, but I think if I were a fish, those would sound pretty tasty!

[Blinky]

*laff*
This is eenie, meenie, miny and mo... and their 200 little friends!
I've been reading, and apparantly they're in most tanks but aren't visible unless they're well fed and the population blooms - like algae, they grow given the right (wrong?) conditions. Fish do eat them, and I'm wondering if lots of food plus having no fish in the tank is what's resulted in my bunch of teeny critters.

[kveeti]

Be careful, Blinky:

http://members.shaw.ca/pete.carriere/comic.jpg

I got that off some site that I can't remember now, when I was researching copepods. I have copepods but mine can only be seen under the microscope.

[Blinky]

:eek:
Oh my!

[Swimfins]

From what I gather copepods are present in all freshwater tanks. I know they are a staple in diet of black ghost knifefish in the wild. Some copepods get up to 20 cm's, most are microscopic. When they get to 20cm's Blinky you might want to ship some up here lol.

[Puffernewbee]

Are you sure they are not just baby shrimp?

[theuselessfew]

Nice work. People buy copepods as a food source for their salt/reef tanks.
Do you have such a tank? Harvesting them would be a PITA. :D

[daveedka]

Copepod is a Genus I believe which contains many species (It's been a while since biology class so feel free to correct me) What you are descibing sound like Planara ( which is a copepod I believe), I have a few and on occasion I have a bunch and then clean my tank better. Last night I saw one that had actually grown to a good 1/2 centimeter maybe more. But usually it's the tiny little fellers on the glass that you see. There are parasitic copepods as well. But I have not had trouble with anything of the sort.

Like many things they are usually in our tanks, but only breed excessively with high organics. So to see an occasional one isn't anything to worry about, but to see a bunch of them indicates the need for some extra vaccuming. With my tank, I often see more of the babies right after a good cleaning, but they generally dissapear within a day or so. If they begin to grow, or I see more than one or two adults, I take it as a sign that I need to be less lazy.
dave

[Blinky]

I don't think they're planaria, the planaria I've seen look more like worms. They move differently than whatever's in my tank, and are long, thin and white, with triangular heads. These guys are much smaller, and appear oval with a tail that's forked at the end. I really wish I had a microscope!
I'll step up the water changes to twice weekly 50%, hopefully that will help. If I had fish that could dine on these critters I'd try harvesting them, but there aren't really enough for a decent meal :)

[RTR]

I would consider the copepods hamless and intresting. Unless they become a heavy cloud...

My Singapore shrimp eat Daphnia, so perhaps the population will stabilize and be controlled.

Planaria are flatworms, not crustaceans.

[kveeti]

Copepods have antenna and caudalsetae (the tail thingys). This is one of mine under the microscope (200X). He’s dyed though, so he’s not really purple, lol. Far as I can tell I have 2 different kinds, though according to the book I have, there are many and different groups have different lengths of antennae.

http://members.shaw.ca/pete.carriere/copepod.jpg

[daveedka]

Planaria are flatworms, not crustaceans

That I knew,
It just didn't dawn on me that copepods were crustaceans. In retrospect I should hav known that ( actually did know that). I just didn't think about it much. I did know that Daphnia were copepods, Just wasn't adding 2 and 2 very well this morning.
Dave

[RTR]

Administer additional caffine - to the keeper, not the fish. :dance

[Beeker]

When I was keeping my Anachris in my 1 gal. tank, I noticed a couple snails and also a bunch of these little white critters. They look similar to that picture. Did they live on the plants? The snails, I think, died. Did they die because of these critters? I liked those little snails. I was pretty upset. :(


I also just found what I think are silverfish in my 5 gal. tank. What do I do? Will they come out if I vac the gravel? How did they get in there? I can only think of the new plants I got today, but I didn't know that these critters can live in water.

[Blinky]

Copepods have antenna and caudalsetae (the tail thingys). there are many and different groups have different lengths of antennae.

http://members.shaw.ca/pete.carriere/copepod.jpg
Thanks for the info guys, and Kveeti, thanks for the picture :)
That's definitely what I'm seeing - mine look a little rounder (and they're not purple ;)), but the basic shape is the same. There aren't many, I can see maybe 50 or so on the glass.
Do these critters swim in open water? If so, they should make a nice supplemental snack for my shrimp :)

[linny]

Hi Blinky, I read your note and was searching for info on those tiny little white things on the glass. I also have some and they are crawling on my foot long clown knife. Should I be worried? How can I rid my 30 G. tank without harming my fish? I have not noticed these guys before and was a little supprised. Also, I have a very pregnant blue gourami. Will they hurt her ? I am new to alot of this and can use all the help I can get. I love the fish and I have just become a member of aquaria. (will my gourami have live babies or eggs?) Thank You. linny

[Blinky]

Hi Linny, welcome to the forum :)
It's probably best to start a new thread so your question gets the attention it deserves, rather than attaching it to something people have already read. There are harmless copepods and there are copepods that are fish parasites; I'd be worried if I saw microscopic crustaceans on my fish.
Try Googling parasitic freshwater copepods, see what you come up with, and if I were you I'd start a new thread.

Are you sure your gourami is full of eggs (they're egg layers) and not constipated or otherwise bloated?

[Tom.E]

Goodness, so much fuss over little copepods.

Kveeti’s photo appears to be a harpacticoid copepod. This Order is more or less a bethnic omnivore on lower trophic organisms and algae.

Blinky; cyclopoid copepods are a more pronounced teardrop shape; that may be your critter. In an aquarium they’re mostly predatory on rotifers and ciliates. In the wild they’ll attack anything their size. Cyclopoids aren’t detrivores, but detritus in a tank will support the organisms that these copepods feed on. Cleaning up the tank a bit should help. My leaf litter tanks (fishless) have strong copepod populations.

As an aside, newborn fish fry can be attacked by cyclopoid copepods (or cyclops) and there are some that are parasitic on fish. I would rule them out unless you actually see them on the fish or see tissue damage.

Beeker; that ‘silverfish’ you have and ‘loss of snails may be predatory insect larvae (mayfly, damselfly,etc…). I use snails and scuds as a prime source of prey for aquatic insects.

Linny; are they crawling or hopping? Copepods don’t crawl, so you can rule them out. Ostracods and water mites crawl.

I’d have to say that over the years maybe a 3rd of the plant orders I received have had copepods brought in with them.


Tom

[Blinky]

Kveeti’s photo appears to be a harpacticoid copepod. This Order is more or less a bethnic omnivore on lower trophic organisms and algae.

Blinky; cyclopoid copepods are a more pronounced teardrop shape; that may be your critter. In an aquarium they’re mostly predatory on rotifers and ciliates. In the wild they’ll attack anything their size. Cyclopoids aren’t detrivores, but detritus in a tank will support the organisms that these copepods feed on. Cleaning up the tank a bit should help. My leaf litter tanks (fishless) have strong copepod populations.

Thanks for the info :)
The tank is pretty much spotless, there's not much to clean up - the substrate is sand, so it's easy to vacuum up any waste sitting on top, and the tank is absolutely stuffed with live plants to a) provide a comfortable environment for the shrimp and b) use up any excess organics caused by accidental overfeeding. I change 50% of the water weekly, I can and will step that up to twice weekly. If these critters are harmless I'm happy to live with them - they're actually kind of cute :)