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I seem to always have creepy weird things in my tank!

the latest i only noticed the other nite.. the inside of the glass is completely covered in tiny pin prick size white 'things' they move around on the glass but mostly sit still i have noticed they swim in the water before attaching to teh glass.. they sort of remind me of baby brine shrimp..

any ideas? are these harmful to my fish?

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Truth doesn't always win friends but it influences them

I am pretty sure I know what you are talking about with the white things. I had them in my tank a while back. Their name starts with a H. but I can't tell you what it is. Maybe try looking through the old threads.

55G Planted tank thread
19G Container Pond
[IMG]http://i4.photobucket.com/albums/y118/Wingsdlc/Ric

Probably planaria http://research.amnh.org/exhibitions/epidemic/planaria.jpg

Usually appear when there is excess food in the tank.
Possibly harmful to fry but not anything major to worry about.

A few waterchanges should reduce the numbers

no i have had a planaria it doesnt look like planaria..

they arent worm like .. more just dots on the glass. ..

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Truth doesn't always win friends but it influences them

You've seen these creatures swimming about on occasions? Ah ... a thought has occurred to me.

On the occasions when they swim, do they seem to spin about in small circles? When they are attached to the glass, do they seem to move around in circles as well?

You could have Ostracods.

Ostracods are tiny aquatic crustaceans - fresh waters and the oceans are teeming with them. They're harmless detritus feeders, but the fact that they've set up shop in your aquarium is a sign that they're making a fine living from your excess fish food.

If you want to get rid of them, the only really successful elimination method is to reduce the amount of food you add to the aquarium. You could resort to chemicals, but that would impact upon your fishes' well being, especially as the only invertebrate toxin that would work well would be copper based. Generally, one should avoid adding copper to an aquarium unless it's vital to do so in order to wipe out a fish pathogen that stubbornly refuses to die using less risky medications.

However, since the Ostracods aren't doing any harm, and are helping to clear up uneaten food in any case, you could just leave them. If, of course, that is what they are.

Do a Google search on "Ostracod" for some images, to see what they look like magnified. Here is a good starting place to find out about them.

Most of them have shells into which they can retract their limbs completely, and the majority of Ostracods that materialise in an aquarium are, under magnification, roughly bean shaped. Don't ask me to identify them to species level, because that requires the services of a professional invertebrate zoologist!


Panda Catfish fan and keeper/breeder since Christmas 2002

I've had something very similar.

Not entirely sure what it was, but harmless nevertheless.

But yes, they would zig zag in the water and could move quite quick.

On the glass, if they got too close to one another or touched, one of them would just dart off somewhere else.

Weird little things. Looked exactly like a grain of sand, with the tiniest little tail.

that does look like them!
ive never heard of these guys before thanks for pointing them out cal.
i did a gravel vac the other day and the amount of food i didnt realise was in there that came out amazed me as im usually careful about how much food goes in. i guess ive been a bit overly generous to make sure my cory fry are eating enough and that tehre are extras for my oto in case hes still hungry.

am gng to definately cut down on feeds and do another gravel vac this weekend.

thanks for your advice!

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Truth doesn't always win friends but it influences them

I first found out about Ostracods from my TFH back numbers ... someone wrote in to their letters section and described an infestation of small creatures which were thus identified by the TFH team as Ostracods.

The original letter (on page 71 of the Aprill 1977 issue) read as follows:

I have encountered a type of living organism in my five-gallon aquarium that I can't identify and can't get rid of. It is a brownish colour and somewhat translucent. Its organs are visible through its shell. The shell looks like that of a clam. The animal is capable of totally withdrawing itself into the shell. It has three segments to its legs which it wves as it swims free in the water. In addition to swimming free, it can adhere to the aquarium glass and rocks. I doubt it is a water flea because its shell is not the ame as a water flea's. I have been told that the organism lives and breeds in excessive fish wastes and uneaten food. Can you tell me what this organism is and how to get rid of it?

The reply from the TFH team read as follows (pages 71 & 72, complete with black and white illustration on page 72):

From your description, it appears that your tank is infested with ostracods. These little crustaceans generally inhabit the decomposing organic layer of stagnant waters almost everywhere in the world.

It has a hard shell and looks like a miniature clam. The organism itself will not harm your fish since it is basically a detrital feeder, but it may harbour other organisms that could harm your fish. Although they make good food for most small fishes, few fishes will actually take them. This could be because of the hardness of the shell.

Once established in an aquarium, ostracods are difficult to get rid of. Before dismantling the tank and sterilising everything in it including the gravel, you might first try starving them to death by removing their food source. In other words, make sure that no uneaten food or decomposing plant matter accumulates in the aquarium. If this doesn't work then you'll probably have to break the tank down. Since they probably won't harm your fishes, the only other alternative is to "live and let live".

More detailed information on these organisms appears in the Encyclopedia of Live Foods by Charles. O. Masters.

Since that letter was published and answered, we now know more. For example, copper based chemicals of the kind used to treat White Spot will also destroy the Ostracods. However, if the Ostracods are present and there have been no instances of fish disease for some time, then it's fairly safe to assume that they're not harbouring something less desirable as a hitch hiker. Some disease organisms of fishes have life cycles that involve parasitism upon multiple hosts - Camallanus nematodes, which are lethal in fancy guppy breeding programmes in particular, are examples of organisms with such a life cycle (digenetic if there are two hosts, trigenetc if there are three, etc). Camallanus lives for part of its life cycle inside Cyclops, which is why American aquarists in particular view these otherwise excellent live food organisms with a wary eye (though this doesn't seem to put off the Germans - their textbooks contain many references to Cyclops as a beneficial live food). If any digenetic pathogens were present in your aquarium, they would have manifested themselves fairly floridly by now, and wiped out a large percentage of your stock (as they are apt to if left untreated - Camallanus is a particularly vicious example) so I can place hand on heart and, without information to the contrary, say that your Ostracods are bot harbouring a digenetic pathogen. Since the only other function that they are performing in there is to dine with gusto on uneaten fish food, digestible parts of fish wastes, and any dead plant matter arising from the plants in the aquarium, they are, actually, a contributor to the nitrogen cycle (and play an important role in the wild in this regard). While not inherently attractive per se, they can provide some amusement as you watch them (and the attempts of some of your fishes to eat them - Lemon Tetras such as the ones I had for nearly 10 years seem to be particularly keen on trying to pick them off bogwood, only to spit them out again!).

Chances are if you dredge your way through some pond muck from any well established pond with a long history, you'll find these creatures in vast numbers. They are part of what is known as the POM cycle - POM standing for Particulate Organic Matter. In other words, bits of dead plant or animal. Making dead things amenable to nitrogen cycle bacteria requires the breaking up of the large mass of the corpse in the case of many fishes, and Ostracods perform this service along with a variety of other creatures - by the tims the Ostracods are getting to work, they're breaking up pieces that are of the order of 1 millimetre in size, having been processed previously by larger animals such as caddis fly larvae and scavenger fishes. By the time the Ostracods are contributing to the cycle, they are converting vast quantities of millimetre-sized particles into debris that is of the order of 20 microns or so in size, at which point bacteria can attack them directly without external assistance. The freshwater sediments of the Amazon River system, for example, probably contain many tens of thousands of Ostracods per cubic metre, and thus there are several million tons of Ostracods munching their way through a similar mass of debris as I type this! Given that their role is, in the wild, a hugely beneficial one, and that their appearance in your aquarium is in part at least a sign of reasonable health (as they need oxygen to function and if your water was bad, they wouldn't be present in any numbers) while revealing that you've been a bit generous with the food ( ) then they're not a major worry. I had them in 1995, but increased frequency of gravel vac use saw their eventual disappearance.


Panda Catfish fan and keeper/breeder since Christmas 2002

I had these in a chiclid tank for several months and had no problems. All my fish seemed healthy and happy. They were white and looked like little grains of sand. Kind of fun to watch.

Hi, Tks this thread has helped me. Ive noticed some in my 10gal..and I know ive been feeding more than usual thats gotta be it. They seem to be only on the edge of gravel line in my tank, will do a quick vac, after my water change in the 40gal.. bye