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What's that bug? How to recognize them

267K views 373 replies 173 participants last post by  Arty and Noodle 
#1 · (Edited)
I don't know if this belongs under "Shrimp" or "General Planted Tank Discussion", the questions about tiny aquatic creatures might usually be posted in the latter one, but I've always used to put shrimp, other invertebrates, bugs and weird things under same classification.

Here's some of the most common tiny creatures found from the aquariums.

Copepods, Cyclops



Size: 0,1 - 0,2 cm, 0.04 - 0.1 inches

Copepods are small and funny looking one eyed crustaceans. They usually move around the tank glass and other surfaces, usually with one short leap at a time. Harmless, cute, there's lots of different coloured species.

Water Fleas, Daphnia



Size: 0,1 - 0,5 cm, 0.04 - 1/4 inches

Water fleas are usually used as fish food. They are tiny crustaceans and are easily recognized of their jerky vertical "swimming". They are completely harmless and really interesting creatures. I call them fat, sad reindeers (well, they look like it :D).


Seed Shrimp, Ostracoda



Size: 0,1 - 0,2 cm, 0.04 - 0.1 inches

Seed shrimp are tiny seed shaped crustaceans. They are usually a bit bigger than Copepods. They move in a same fashion as Copepods, eating all kinds of nice things from the glass/plant/etc. surfaces and you can see them walking inside the substrate too. Sometimes they swim in open water looking like drunken bees. Here's a really young CRS baby looking at a seed shrimp. Really cute, harmless.

Freshwater Limpet - Acroloxus lacustris




Size: 0,1 - 0,8 cm ; 0.04 - 0.3 inches

Since freshwater limpets, Acroloxus lacustris, are so small and also move really slowly, it might be hard to identify them as snails. They are small and can't do much damage to plants, but since they are small, it's impossible to find and remove eggs and the baby snails. Harmless.

Something that looks a bit similar are Nerite eggs. They are singular, white, hard, round or oval shaped and about 1 - 2 mm in diameter.

Tubifex



Size: 2 - 5 cm, 3/4 - 2 inches

Red, yummy worms (used as fish food too) which live inside the substrate. If disturbed and dig up, they will form a ball, if left alone, they will gather pieces of sand/gravel around their body forming a sort of tube where they live in and they'll stick their head out of the substrate looking like red hairgrass. If there's lots of them, the substrate is too dirty and might be good idea to do something about it. Only a few Tubifex in the substrate isn't anything to worry about though. They are harmless.

Nematodes
Size: 0,1 - 0,3 cm, max. 0.1 inches

Nematodes are small, thin, white/transparent free-living roundworms and the "swim" moving themselves in a wave like pattern (well, forming an S shape). If disturbed, they will swim around wriggling briskly. You can find them from the substrate and they are the ones that might appear from the filter when you turn it on. These ones are harmless, but as with any other "pest", if there's too many of them, you are either overfeeding or just not keeping the tank clean enough of debris, decaying plant matter.

Planaria, flatworms



Size: 0,3 - 1 cm, 0.1 - 3/8 inches

Non-parasitic flatworms. Crossed-eyed grossness, just pure yucky! The only small creature I dislike (I get shivers down my spine even thinking about them). If you split it, it will regenerate and you will end up having 2 planaria. There seems to be several different colours in the common ones found in aquariums, transparent, white, brown and red. There's actually nothing really horrible about them, but they can bother small shrimp and snails and might eat fish/snail eggs.

They love shrimp pellets, pieces of meat, dead fish/shrimp and they will also eat small live creatures if they can catch them. They move on the surfaces, even under the water surface and are most active by night. If disturbed, they will retract themselves (shorter and wider), let go and drop down to the bottom.

Hydra



Size: 0,3 - 1,5 cm, 0.1 - 1/2 inches

Hydra are beautiful, but a wee bit annoying creatures. They spend their life attached to surfaces (plants, glass, filter, decoration), they can move a bit, but usually don't have the need to do that. If disturbed, they will retract their tentacles and body to small buds. They catch small creatures (copepods, Daphnia etc.) with their tentacles which can sting, making it easier for them to haul the pray in to their mouth opening. They pose no threat to adult fish, shrimp or snails (might cause some irritation if they touch the Hydra), but newborn fish and shrimp fry are in danger.

The species in the picture is Hydra viridissima and the green color comes from algae living inside the hydra.

Bryozoa, moss animals



Size: individual creatures are only a few millimetres long, the colony can be tens of centimetres long

Bryozoans are interesting colonial creatures. They look a bit like corals with the hard skeleton structure of the colony. The individual creatures, zooids, are inside their own small part of the colony and they eat small particles (phytoplankton, zooplankton) floating in the water by guiding them (and water) towards their mouth opening with the fan like tentacles. If disturbed, the zooids will retract their tentacles inside the colony walls. They are harmless and really interesting.

Springtails, Collembola



Size: 0,1 - 0,3 cm, 0.04 - 0.1 inches

Springtails are cool hexapods. They are used as live food for fish that eat from the surface, for example small Betta species and labyrinth fishes. You can find them more often from soil or leaf litter than from the water surface, but once in a while they will appear on the floating aquarium plants. If disturbed, they will spring to safety releasing their "spring" (furcula) that's normally bent under their body. They can jump surprisingly far (several centimeters). Harmless and cute.

Mosquito larvae




Text coming later.

Bloodworms



Text coming later
 
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#63 ·
Freshwater Isopods...

Great thread, and fantastic pictures...unfortunately my camera is not so good...and my photography skills are worse, but here's a photo of a local freshwater isopod/amphiopod that turned up in one of my tanks.

They appear to be harmless and just snack on left over food and detritus in the tank. I probably wouldn't want them in a tank with egg laying fish, but I'm currently keeping them with gammarus (scuds) and cherry shrimp, and they are an interesting addition.

A little like an aquatic sow bug...

 

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#64 ·
Awesome thread! I'm new to this forum (because of the arrival of my new RSC's). Also arriving with them were some plants (thanks Jon) and quite a few critters - seed shrimps, cyclops. One thing about cyclops: The female carrying egg sacs are quite different.. like this(Darkfield, x100.)
:
I was quite puzzled until I found this picture from the following site. Great info. http://www.micrographia.com/specbiol/crustac/homeclad/clad0100.htm
 
#72 ·
If you have a magnetic scraper, put it in the tank with the highest light output. Place it near the surface and within a week it should be covered in algae (well at least the top), take it out and put in your shrimp tank, then the next morning check it out, usually there will be planeria swarming it, then you can just take it our and wash it off... Or another method I've used to dwindle their population is to take a leaf (preferably a long broad one like those of swords) that is either covered with algae or dying and put it in the shrimp tank, same idea, wait overnight (or maybe 2 or 3 nights depending) and let the planeria swarm it, then you can remove it and a good number of planeria at the same time. These two methods help me remove roughly 20-40 worms at a time...although I will say, the scraper will become very slimy from the worms...

Kevin
 
#74 ·
I usually have it within 3 inches of the surface (I also have plecos that like browsing the algae, so that close means it maintains a good coat of it. When I first tried this my cherries and nerites swarmed it, and after all the algae was gone the planeria swarmed it for the residue. Then the next time they swarmed it before the cherries got a foothold. You just have to find the method that is good enough for you. You can always set a bait trap for them as well. Take rigid tubing or something of that nature and place bottom feeder pellets in it at night, usually by morning either snails or planeria are swarming the insides. However, you can also wait an hour after turning of the lights and check the tube, usually planeria have indeed swarmed it by then...

Kevin
 
#75 ·
This morning I had looked into my tank and saw this Planeria crawling on the glass. :eek: It was HUGE! It was a little over an inch long when it was stretched out. I quickly grabbed the camera but was unable to get a clear pic but I did get a fuzzy one. :icon_neut I them grabbed it out of the tank with a paper towel and took pics of it on the paper towel. The thing was creepy and eeewwww!



I kinda smashed up part of the face getting it out of the tank..as you can see on the napkin, there are bits of him....



He had measured 5/8 of an inch long - after being out of the water for several minutes and drying up...He measured longer than what was stated at the begining of this sticky.... But I neglected to get a pic of him against the measuring tape (kinda hard jigglying the camera and holding the measuring tape, at the same time)
 
#78 ·
What is this?

I have these white things in my 10 gal. and I need to know if I should be worried.

What is this? Does anyone know? Should I be concerned?





I found this on the parasite sticky, It kind of looks like this. How do I get rid of them.


This is not a planaria with a spine and rudimentary legs. It is an Australian LEECH! Apparently the "spine" is it's developing young, and when they become free swimming, they attach itself to the mother and look like a billion tiny wiggly legs. Totally disgusting and mine was about a fourth of an inch long.

Actually, I come to find a year later, it was some sort of snail leach. Even more disgusting.
 
#81 · (Edited)
I was talking to a friend about some ostracods on another forum. She informed me during the conversation that Cyclops (below) are potential carriers for camallanus. I thought that was worth passing along because I always thought they were completely harmless. Some of the conversation:

they [cyclops] are generally not dangerous, but it is possible for cyclops to act as a carrier of camallanus worm larvae. The presence of cyclops doesn't mean "OMG--my fish are all going to get camallanus and DIE!" and indeed, I've had them in my tanks without incident, but they are capable of carrying it and it does happen in aquaria. If they are cyclops, and their origin unknown, it's worth keeping an eye out for symptoms of camallanus worms, especially if the tank is home to guppies.
Copepods, Cyclops



Size: 0,1 - 0,2 cm, 0.04 - 0.1 inches

Copepods are small and funny looking one eyed crustaceans. They usually move around the tank glass and other surfaces, usually with one short leap at a time. Harmless, cute, there's lots of different coloured species.
 
#82 ·
I had some white worms swimming along my substrate and also in my HOB filters. I finally managed to catch one of them and put it under the microscope. Enjoy! The second picture is a weird looking bug in the same water as the worm. If anyone can id it would be nice.



 
#83 ·
I dunno about the worm, but the bug almost looks like a diving spider, only a LOT smaller. It's really hard to tell with it being twisted around like that.

Tommy
 
#89 ·
So, many of us (including myself) have squiggly white worms that end up in the water column whenever we disturb the substrate.

Something like this.

All of the info that I've come across links it to the Stylaria lacustris. A species of oligochaete that is commonly found in freshwater systems feeding on waste.

The general consensus is that they're harmless to us and our fish.

Magnified Picture

Video #2

Brief overview of Oligochaeta

 
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