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FAQs on Small Freshwater Crustaceans

Related  Articles: Forget Crawfish Pie, Let's Make a Crawfish Tank! By Gage Harford, Freshwater to Brackish Crabs by Bob Fenner, Terrestrial Hermit CrabsInvertebrates for Freshwater Aquariums by Neale Monks,

Related FAQs:  FW Crustaceans 1FW Crustaceans 2, FW Crustaceans 3, & & FAQs on: FW Crustacean Identification, FW Crustacean Behavior, FW Crustacean Compatibility, FW Crustacean Selection, FW Crustacean Systems, FW Crustacean Feeding, FW Crustacean Disease, FW Crustacean Reproduction & Small Freshwater Crustaceans Groups, by Genus: Triops, the Amphipods Which Are Gammarus (Scuds), Cyclops, & Crustacean Selection, Crustacean Behavior, Crustacean Compatibility, Crustacean Systems, Crustacean Feeding, Crustacean Disease, Crustacean Reproduction, Freshwater Shrimp, FW Crabs, Terrestrial Hermit Crabs, & Marine Hermit ID, Hermit Behavior, Hermit Compatibility, Hermit Selection, Hermit Systems, Hermit Feeding, Hermit Reproduction, Hermit Disease/Health, & Crayfish FAQs, Crayfish 2, Crayfish ID, Crayfish Behavior, Crayfish Compatibility, Crayfish Selection, Crayfish Systems, Crayfish Feeding, Crayfish Disease, Crayfish Reproduction,

Are these Gammarus shrimp?     6/2/16
Hello wonderfully helpful people!
<Howsit Sab?>
I turned on my light in my 10 gallon freshwater tank today and was greeted with the sight of tiny crustaceans zipping around that most definitely should not be in there. They're brown and tiny, only about 3/16 of an inch.
I've managed to catch 4 into a container, but there's at least a couple more. After scouring the web I came to the conclusion that they seem to be Gammarus shrimp, but would like your expert opinion.
<I do think this is Gammarus as well>
Provided that they are Gammarus shrimp, should I put them back in the tank or should they be removed?
<I'd keep them as useful scavengers. Neat animals>
Thank you very much!
<Welcome! Bob Fenner>

Re: Are these Gammarus shrimp?     6/2/16
Hello Bob!
Is there a chance of them taking over the tank or harming my Pygmy cories?
They're kind of freaky looking.
<Not much chance of either; however if the Corydoras or other egg-laying fishes were spawning, these might be consumed. BobF>
Re: Are these Gammarus shrimp?     6/2/16

I was hoping the Corydoras would spawn but I read that these shrimp hide in the substrate and can't be eradicated,
<Mmm; well... can be... by chemical means... Poisons that target Arthropods... And to some degree via purposeful predators>
so I suppose that dream is out the window. I guess I'll return them back to the tank then and let them eat the detritus. Thank you for your help once again!
<Cheers, BobF>
Re: Are these Gammarus shrimp?      6/7/16

Yikes I definitely don't want to use poisons. Is it common for tanks to acquire a variety of tiny crustaceans?
<Yes; healthy ones do quite often. Especially if stocked with live plants>
After finding the shrimp I looked much more closely at my tank and noticed a tiny white dot, smaller than a grain of salt, swimming towards a moss ball and climbing up it. When I sucked up the shrimp I also sucked up little round black thing smaller than the white thing that swims around rather erratically. If this is normal I definitely don't mind having a nice varied ecosystem going.
<I am of the same philosophy, practice. Perhaps an inexpensive microscope is in your future? Fascinating fun.
Bob Fenner>

Little Bugs Swimming In The Aquarium    1/21/07 I am in desperate need of some answers concerning these nearly microscopic "bugs" which persist in my aquarium despite amazing odds against them. Fish store owners have looked at me as though I have lost my mind when I try to describe my problem, so hopefully you can help. I have a 2.5 gallon freshwater aquarium which originally contained 1 male Betta. I noticed one day when I turned on the tank light that there were small, nearly microscopic, white specks on the (in)side of the glass (actually it is acrylic). These white specks moved with purpose, much like an insect would. They moved quickly considering their small size, but slowly from my standpoint. It is my impression that it is the 'adults' of these bugs which are free swimming and appear to jerk slightly from side to side as they swim upwards or horizontally; however, it could just be that some cling to the glass, while others lose their grip and swim around. The fish store owner gave me the strongest aquatic insecticide he had available, and I took it home and treated the tank twice. I did have some small worms also crawling on the glass, which all died, but these "bugs" weren't even phased. I moved my Betta into a Betta bowl, and inadvertently transferred some of these bugs, too. The next time I moved my Betta, I did so by hand to a 1 gallon bowl, and so far it appears to be free from the bugs. Still, I emptied the 2.5 gallon aquarium and set it outside under an awning to let it completely dry out in the frigid winter air for about a month. Just after Christmas, I set up the aquarium again, scrubbing the sides and churning the gravel to clean as best I could, and left it to filter without fish or plants for about 3 weeks. After that time, it still seemed clear of bugs, so I put in my new goldfish to house until I get my new 36 gallon aquarium cycled and ready for fish. Just this morning, I turned on the light of the 2.5 gallon aquarium and behold! Upon close inspection, small white specks are moving around on the glass again! How did they come back? What are they? How can I prevent them from spreading into my new aquarium when one occupant of that aquarium will be a fish who has been living with these bugs for what will come to be weeks? Can I stop this bug infestation before they are inadvertently transferred to my new aquarium (are they even bugs)? My 5 gallon aquarium temporarily housing my other goldfish has been and is still free from such horrible little creatures. What in the world happened with the smaller aquarium? Could the bugs have come in on a plant from PetCo which I bought when its roots were encased in nothing but gel? Thanks for your time! Cami < Treat the tank with either Fluke-Tabs or Clout. These medications will kill most invertebrates. You need to retreat as per the directions on the package because the medication may not be effective against the eggs. I Think you have a sort of daphnia or water flea. They come in with plants or sand. The eggs can survive drying out. They are unsightly but usually harmless.-Chuck>

Little Bugs In The Aquarium II    1/21/07 I forgot to mention that I want to be rid of these bugs, not just for peace of mind, but because the free swimming form of them irritated my Betta. They made him dart around as though they bothered him. Now that he is free from them, he is acting normally again. My new goldfish in the tank with the bugs seems to dart around too. < The medication I recommended will take care of these bugs, even if they are fish lice.-Chuck>

Crazily mis- over-stocked FW sys.... w/ induced prob.s... Crazy! Oh, and HH ID    7/23/09
I was wondering if you could help me out with my Freshwater tank problem.
<Am trying>
I have a 90 Gallon tank. which is home to 3 Aruwans, 3 Oscars, 2 Silver dollars, 1 clown knife fish and a Giant Pink Gaurami.
<Yeeikes! Way too crowded... and only going to get worse... All this, these animals won't live well or long in this small volume>
The tank has 1 External Filter , and two submerged filters, 2 air supply pumps. Gravel Substrate and two tank ornaments.
The water temperature is at a steady 78 deg and changed 25% every two weeks.
<I'd change this amount weekly>
About a week ago I've noticed a lot of tiny white bubble like creatures in the tank, very similar to tiny fish eggs. Now they seem to be moving around the tank and sometimes cling on to my Oscars. Yesterday my clown knife fish died unexpectedly ( No symptoms of being sick or hurt).
<Stress alone...>
These white creatures are now all over the gravel and some on the sides of my tank as well.(Photo attached)
can any one tell me 1).What are they? 2) How can i get rid of them?
<Small crustaceans of some sort... Perhaps Cladocerans... not harmful... Best to "be rid of them" by simple vacuuming, cleaning of the gravel... BUT, you need NOW to move, separate the life you list... READ re the needs of these species. They can't all live in a ninety. Bob Fenner>
Any help would be greatly appreciated.
Thank you

Re: mis- over-stocked FW induced prob.s   07/23/09
Thank you Bob Fenner for your advice I will try it.
<Ah, good>
Hopefully I will be able to write back "problem solved" Also I have just setup another tank so will be moving the Oscars out soon.
Thank you once again.
Vishwas Shetty
<Welcome my friend. BobF> 

Unidentified freshwater critters  12/14/08 Dear crew, Can you please help me identify these bugs that are running amok in my freshwater invertebrate tank (Red Cherry Shrimp and Melanoides sp.). I don't think they're parasites, they seem to eat whatever the shrimp eat and hang out a lot in the sponge filter and in the sand. They do swim in the water column and appear to have a pair of antennae when observed with a magnifying glass and measure maybe 1-2mm. I don't intend to try to eradicate them as they don't appear to do any harm, but I would like to know what these might be, just out of curiosity. Any help is greatly appreciated. Thank you, Evan <Evan, I can't really be certain from the photos you sent, but my assumption is that these are nothing more than copepods. They're completely harmless, and indeed edible, and should be taken by some of your fish, particularly anything that sifts the sediment (for example dwarf cichlids). Now, when invertebrates "run amok" in aquaria, it's often a good sign there's an excess of organic matter, i.e., food for them to eat. So cut back on the portions at dinner time! If need be, stop feeding altogether for a week, and the snails and shrimps will do just fine on algae alone. Otherwise, don't worry about them too much. Heck, if this was a marine reef tank, you'd be happy to see these chaps! Cheers, Neale.>

Black Pepper Size Critters in FW Tank - 7/2/08
Greetings from Georgia! <And reciprocal salutations for Hertfordshire!> We apologize is this is covered elsewhere on the site, as we found reference to white copepods, but not our 'bug.' Our 125 gallon community FW tank (1.002 salt) has been up 15 months. It has 2-3 inches of LFS gravel. <Ah, 1.002 definitely qualifies as "brackish" -- that's about 4-5 grammes of marine salt mix per litre of water, or about 10-15% the normal salinity of seawater. Great for livebearers, killifish, and other species that appreciate slightly saline conditions.> For the first time, upon vacuuming the gravel and changing water, our white buckets had 100's, perhaps 1000's of black (dark brown?) specks smaller than pepper grains moving furiously in the bottom of the siphoned water yesterday. I have never seen them before. <Likely only copepods, ostracods, aquatic insects or similar.> They seem to cling to larger detritus in the bottom of the bucket. Under a hand held magnifying glass, no visible legs, eyes, spots, antennae, stripes, etc turned up. Still looked like black pepper. Our fish are healthy; these are not on the fish that we can see. These are not visible in the tank. <OK.> They died pretty quickly in the sunlight in 2" of the water outside at 90 degrees F daytime temperature. <How mean!> What are they, are they harmful or good for the tank? <Harmless; indeed, somewhat beneficial as they will be helping to speed up the decay of detritus in the substrate, preventing anaerobic decay. They will also provide a certain amount of food for species that graze on or sift the substrate. If you have an excessive number of them, it likely implies that there's a lot of organic matter in the sediment, which implies you are either overfeeding your fish or under-cleaning the substrate. Either way, controlling the food supply will go a long way to restricting the population of these organisms.> Many thanks, Don <Cheers, Neale.>

Re: Black Pepper Size Critters in FW Tank   - 7/2/08
Many thanks, Neale, we appreciate your advice. <Most welcome!> I have visited your area years ago, I think it dates back to the Bronze Age; I visited after that! <I see!> Thanks for clarifying that we are indeed "brackish." We will watch the overfeeding. <Very good.> Your answer begs the question: Since we need (want?) the gravel substrate to anchor our many plastic plants (oxymoron?), the UGF is along for the ride and we don't see getting rid of the UGF, it does the job. <Quite; UGFs can work very well, provided their limitations aren't a problem for your particular set-up. Turned into a reverse-flow system by adding a canister filter to the mix instead of powerheads/airstones and you have one of the single best filtration systems around.> What is the thinnest we can go on depth of the gravel and still accomplish the UGF function? We understand too deep is bad (anaerobic dead spots), and too thin does not accomplish the mission. <I'd recommend 8 cm/3". Does of course depend on the grade of the gravel; finer gravel will provide more surface area per unit depth.> It would seem that vacuuming and cleaning are simplified with a minimal thickness of gravel. We operate two Aqua Clear 400 power heads (1 in each back corner), and also a Fluval 405 and a Fluval 305. Again this is a 125 gallon tank with no live plants, and approximately 50 community fish. The gravel is on a raised plastic tray. We remove plastic plants, caves, etc to gravel so there is never a dead spot due to a fixed decoration. <Ah, I suspect a reverse flow system is precisely what you need. All you do is connect the canister filter outlet to the inlet of the UG filter plate. So water gets filtered mechanically by the canister (removing silt and organic debris) and then pushed from underneath the filter plate up through the gravel into the tank. As it goes through the gravel, the ammonia and nitrite are removed. The really big advantage is that the gravel now becomes 'self-cleaning' because silt and debris can't settle into it; instead the upwards flow of water constantly cleans the gravel, pushing fine particles into the water column.> Thanks again for your time and efforts toward this fishy fun. Cheers, Don and Rosemary <Cheers, Neale.>

Re: the incurable itch, now unid'ed FW crustacean  9/2/05 Okay, I just seen something.  I was feeding my fish and crawling on one of the apple snails was a bug, it looked like a common flea that you would find on a dog or cat.  It was brown and big for an aquarium bug. I thought it was a bug that fell in my tank and was going to drowned but it just crawled around on the snail and it was carrying a little sac.  It carried the sac some where near the snail's eye and then I lost track of it because the snail retracted into its shell, now comes the weirdest part.  I think the bug crawled into my snails butt and is just sitting there because I can see a brown thing through the skin and I don't think it is poop because it isn't falling out. I am not 100% sure though. I just put the apple snails in the tank a few days ago and I KNOW they are healthy because they were born here in a 20g tank down stairs where they have lived without fish for several months. My step dad also has some of the snails including the mother in his 60g tank and I have never before seen anything like this bug in my tank.  It is way too big for me to have missed crawling on one of my fish.  Any ideas? <Is very likely one of many freshwater crustaceans. Very likely not harmful>   It didn't look like fish lice, or fish fleas, it was way too big, it was like at least the size of the apostrophe on the keyboard.   Oh yeah, also that is not a rock on the bottom it is bog wood.   <I see, thank you> Again thanks for your help. I need it!  I have to admit that I am sort of freaked out about this and I am feeling pretty down. I had high hopes about getting back into the hobby and was planning on adding either a few Kuhlis or some dwarf frogs to the tank but it seems like my tank will never be healthy. <Mmm, give it time... could be chemical/s leaching from the bog wood... try removing this for a few weeks, the carbon...> I have had problems right from the start despite all my efforts.  I hope I can get through this with all my fish and my tank intact. <There is something likely very simple at play here... to be found, fixed in time. Bob Fenner>

Help me I've got fleas I have a 6 gallon fish tank with 4 fancy tailed guppies, a Chinese algae eater, and an ugly sucker fish of some sort. I do not know the name of the sucker fish, but believe that after I bought him and put him in my tank, is when the problem started. I have some sort of fast breeding crustaceans taking over my tank. I have broken my tank down and cleaned and cleaned and cleaned it on several occasions, but they keep coming back. They seem to start down in the gravel, then you can see them look like they are floating up to the top, just to swim back down. After a week or so, they will start up moving and down the walls of the tank, almost marching like an army.  I have asked several pet stores and they sell me stuff to treat the fish with, even though I have tried to tell them that the fish are fine. The fish will not eat these things and these things do not attach themselves to the fish. I even dipped some out of these things out of the tank and took it to several places that sell fish. They don't have a clue what they are! I looked at 3 under a 5X's magnifying glass. They are light tan color, shaped like a football with black dots (I could not see any legs), and feel like a piece of sand. I hope you can help me with getting rid of these, because I really do enjoy having a fish tank.  < I think you have a species of daphnia or water flea. Some small red species are edible to fish, but others are hard and fish do not like them. I suspect that your gravel or some live plants may be responsible. If you used a inexpensive natural sand then I think the local river bed may have contained some of these critters and it took them a little while to reproduce in the numbers you now see. The red ones feed on algae particles in the water. In fact some green water would be required to keep them alive. I have seen something similar to what you describe in with pond plants and duckweed all the time but I am not sure what they eat. Since you have such a small tank I would take the tank apart. Then I would wash the sand thoroughly in a five gallon bucket along with the decorations. Carefully add a cup of bleach and let everything soak. The water fleas should be floating to the top of the bucket dead. If not then add another 1/2 cup of bleach. If everything is dead then I would get some rubber gloves and wipe down the interior of the tank with the bleach mixture. Rinse everything good at least three times. Put everything back and check the chlorine levels in the water. Add a water conditioner to remove any remaining chlorine residue. Your tank has now been sterilized and you have no biological filtration so you will have to carefully watch the ammonia levels until your tank gets cycled again Don't add any of the water from the container with the fish. Pour the fish into a net and place them back in the tank.-Chuck>

Is this an isopod?  4/6/07 Dear Crew Members, <Deborah> I've spent the last few hours on WetWebMedia trying to find an answer to this question with no clear answers so, I'm once again turning to the crew.  The filter on my 15GAL Fresh Water tank gave out last month and, while disposing of it, I noticed some little critters attached to the BIO-wheel.  They looked very similar to isopods. <Yes> Since I didn't see any more, I forgot all about it.  Today, I was doing a water change and saw multiple shells (possibly exoskeletons) from these same little creatures inside the tank. They all appeared to be dead but, they had gotten under the lip of the tank and into the light casing leaving remnants behind.  All of my fish look great and none have anything attached to them.  I'm attaching a couple of pictures in hopes that you can tell me what these are. Are they an infestation? <Mmm... I actually doubt it/this... as you would very likely see a more than decimation of your fish population... chew marks et al.> If so, how do I get rid of them?  Either way, how are they normally introduced to the tank?  Any help will be greatly appreciated, as always. Thanks, Deborah (tank rat) <These may be isopods... but more like "Wood Lice/Louse"... just having a drink so to speak... See Google with the term, "Freshwater Isopods"... and look at the images... Bob Fenner>

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