Bugs and worms in aquarium and shrimp tank. Are they harm or harmless??

Nov 18th 2015

What's that bug? How to recognize them

One day you just stare at your aquarium or shrimp tank and see some different creatures appear from nowhere. They are moving on glass, creeping around, swimming all over the tank. They can be tiny or bigger. You realize that you never brought them in and ask how can they get in the tank. Are they harm or harmless for your shrimps, fish and plants??? Thanks to Rain- (a member on The Planted Tank forum) for explaining these bugs in this article

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

Copepods, Cyclops

Report this image

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

Report this image

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 jerkyvertical "swimming". They are completely harmless and really interesting creatures. I call them fat, sad reindeers (well, they look like it

).

Seed Shrimp, Ostracoda

Report this image

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

Report this image

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

Report this image

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

Red, yummy worms (used as fish foodtoo) 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 overfeedingor just not keeping the tank clean enough of debris, decaying plant matter.

Planaria, flatworms

Report this image

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

Report this image

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

Report this image

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

Report this image

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

Report this image

Text coming later.

Bloodworms

Report this image

Text coming later

Source: http://www.plantedtank.net/forums/88-shrimp-other-invertebrates/40061-whats-bug-how-recognize-them.html