Interesting little buggers...

7yl4r

My 20 gal aquarium has become home to about a thousand tiny bugs.

I would say they're about the size of a pin head and oval in shape. They stay on the sides or bottom most of the time, but seem to be quite capable of swimming around.

There's no way I can get a picture of them but if I had to guess I'd say they probably resemble something like a short-legged flea or maybe a beetle/ladybug (but much smaller of course).

I'm almost positive they came in on an umbrella plant clipping I planted in my tank.
( http://en.wikipedia.org/wiki/Cyperus_alternifolius )

I've decided to let them stay for a while because they seem to be astonishingly good at eating the algae off the sides of my aquarium, while seemingly not causing my plants any harm.

So... two questions:

1. Any Idea what they are?

2. Any idea what easy to keep fish might help curb their numbers?

FrogHerder

Copepods? Aquarium (and Pond) Answers: Cyclops, Are these freshwater copepods dangerous in an Aquarium?

You'll probably need a microscope if you're interested in a positive identification.

7yl4r

Unfortunately I don't have space or $ for a microscope right now, but I was looking for just a general idea.

I don't think they are cyclops, but based on what Wikipedia says about copepods I'm happy saying that they are probably some species of copepod.

So what do you think would be a good fish/critter to eat loads of these things? My betta never seemed interested in them. Just about any fish small enough to care about something that size?

Angel079

What do the lil buggers look like? You positive its not planaria you're dealing with there (lil white 'worms' search googel image results for reference pictures)?

FrogHerder

Could also be water mites, which are arachnids rather than crustaceans. We also have some in our betta tank, and I'm curious about this myself.

If you have porous substrate, most of them are probably in/under it where most fish can't really get after them. I know saltwater gobies feed on them. Maybe do some reasearch into freshwater gobies? Maybe smaller loaches? I would also guess that a good number of invertebrates/insect larvae feed on them but the ones that I can name off the top of my head would eventually mature into flying insects or become a quick snack for a Betta.

7yl4r

@Angel079
They're definitely not any kind of worm; as far as I can tell they have egg shaped, ovular, or round bodies.
I looked at some with a bright background and they appear to have several very small limbs on the underside of their bodies, more towards their front; these 'legs' are small in proportion to the body (probably about half as long as the body is wide) and they appear to use them to swim. Also, they are dark brown in color.

On an unrelated note though... when going through some of my gravel I did find a very interesting worm I could only describe as sea-cucumber-like.

@FrogHerder
I think they do resemble water mites (my initial conclusion 6mo. ago) but I'm just not so sure. Several pages google comes up with says that they pretty much scavenge on whatever is around, but I'm pretty sure mine just eat the algae off my tank glass(plastic, actually); back when I had actual noticeable algae you could see the spots where they had gobbled it up. I suppose this is probably the best guess so far though.

As for substrate, mine is mostly gravel with small amounts of sand and sandy soil mixed here and there. There are many decomposing bodies on the bottom(and I vacuumed Sunday!), but virtually no live buggers. They also don't seem interested in the small amounts of algae growing on my rocks... Just the glass. They spend pretty much all their time either sitting on or scooting around on it... that is... when they're not caught in a current and being blown around.

As far as my Betta bothering any potential future inhabitants, that won't be an issue; he died a couple weeks ago. =/ sure miss 'im.

And finally... I've always liked gobys. I hadn't considered freshwater varieties. Seems like a good suggestion, wikipedia says the biggest problem with smaller freshwater gobies is feeding as they prefer live foods. I may look into that. =)

Angel079

I'd rather wanna make sure first to ID for sure what you're dealing with there rather then buying a fish who's supposed to eat them.
For all you know you're dealing with some type parasite there and then what!?

7yl4r

Certainly something worth considering. I'm inclined to think that since my betta never seemed bothered by them, that they are not primarily parasitic. Also, I am waiting several weeks before adding any new fish in hopes of 'starving' parasitic creatures. I suppose there are many potentially problematic creatures/bacteria/what-have-you that can survive without a host though. Do you think this is an effective method?

Angel079

There's so many gazillion possibilities what this could be.... You're the only one that see's them not us, so I'd recommend just googel image search till you know for sure what it is.

FrogHerder

One thought that comes to mind is possibly contacting a local HS or college biology dept. The educators there may jump at the chance to do some real science and help you do the taxonomy if you have the time to run them a sample. Probably safest for any future tank residents that way. As you mentioned, a very good number of parasites can go quite awhile in dormant stages or live on in intermediate hosts. Also a good number of opportunistic organisms that will feed on either live fish or detritus and could cause problems. Also a very good chance that it's just normal/harmless critter going through a population boom. Without a microscope (and maybe some tax books), it's just impossible to tell.

Sounds like there are no live fish left in the tank? If you were having trouble with fish dying off, that is something altogether different. If you have reason to suspect pathogenic bacteria or virii - maybe consider steriliziing everything and starting fresh?