How do micro-fauna make their way into our tanks?

[RogueAquarium]

Are seed shrimp cysts so small they are born along on the wind with dust particles? Do they somehow survive the chlorine and come in with the tap water? I notice them more commonly in my dirted tanks, do they possibly just lay their eggs EVERYWHERE and hope that someday that patch of dirt will be submerged long enough to hatch out and reproduce, similar to a fairy shirmp? That's just ONE of the THOUSANDS of micro fauna that could be found in the average healthy tank.


I have been VERY curious about this for a long time. I know we have disproven the old Greek hypothesis of "Spontaneous Generation" but looking at and thinking too deeply about my aquariums can have me questioning sometimes.

Edited July 10, 2021 by RogueAquarium

[Guppysnail]

I know some things such as hydra do creat cysts that actually do float around as dust particles. Seed shrimp I have no clue. Maybe…bear with me I’m actually not making a joke….they are like daphnia and can exist forever in cyst form and survive freezing and dying like daphnia, and pre ice age they were in the area the dirt was from, might have been a pond/lake Then frozen and dried and miraculously revive in our tanks. 

[ARMYVET]

The aquatic world is the most misunderstood part of our planet.  We know more about space than our own rivers and streams. Sad but true!

[gardenman]

I suspect a lot is airborne. I live many miles from saltwater, but when I started a marine tank, I had marine algae growing in it within days. Where did it come from? I didn't put it there and yet, there it was.

[ARMYVET]

On 7/10/2021 at 8:11 AM, gardenman said:

I suspect a lot is airborne. I live many miles from saltwater, but when I started a marine tank, I had marine algae growing in it within days. Where did it come from? I didn't put it there and yet, there it was.

You may very well have put it in and not knew it.  Salt mixes to make salt water contain so many trace elements some of which is algal spores.  So it is possible that when you mixed up your saltwater you were putting in the fundamentals for algal growth as well.  Now if you get fresh saltwater from the store ...they get it from the ocean and you have a ton of stuff coming along for the ride..LOL

[NanoNano]

My thinking is that municipal water chemical treatments generally focuses on things that will cause unpleasant or serious human illness, cancerous chemical contaminants, and things that can make water look or taste "unpalatable".  Things that don't fit those criteria directly aren't really a focus and if efforts to control the previous issues don't render things dead,  out the tap and into your tank they go.

[HH Morant]

I have put a lot of things in my tank, and each could be a source - live fish, plants, wood, substrate, soil, root tabs, rock wool on plants, my fingers (hands, arms), fish food, pleco caves, superglue, filter media, medications, water treatments, and other stuff I am overlooking right now (like water?). And maybe some things come in that are airborne. Who knows? Anything that is airborne outside can come inside on my hands, hair, and clothes.

[ARMYVET]

Try working on an outdoor above ground pond....all kinds of stuff end up in that thing...LOL  

[Eric W-Farmhouse Fish Room]

It's a great question.  I wonder if some of this stuff is in foods as well, particularly when feeding live or frozen.  I never saw any sort of detritus worm or leech or anything like that until I started feeding live baby brine and frozen baby brine / bloodworms.  Of course I did not start feeding those things until I got MTS and a lot more fish, so it is possible I'm just experiencing the law of probabilities.

[CT_]

On 7/10/2021 at 12:10 PM, ARMYVET said:

Try working on an outdoor above ground pond....all kinds of stuff end up in that thing...LOL  

I just started finding snails in mine.  I threw in a random ramshorn but i'm finding the sideways curly kinds now.  If it were indoors I'd kill it with fire, but outside, the more the merrier. 

[gardenman]

Even rogue fish can turn up in an outside pond. Fish eggs are sticky and birds getting a drink in a stream can find fish eggs glued to their feet that then fall off when they visit your pond for a drink. Many pond keepers have a "What the heck?" moment when they find a fish that shouldn't be there in their pond. 

[Chloe and Speckles]

A Youtuber I follow called Fins and Whiskers deliberately puts a few pieces of hay meant for feeding gerbils in her otocinclus tank. The hay creates biofilm, and microorganisms appear and feed on the biofilm for her. 

[mountaintoppufferkeeper]

Nature is a better friend than foe. All my tanks eventually have the same microfauna no matter how I isolate them from each other.

I'd say its a combination of airborne particles/spores and dormancy depending on the microfauna. Air, substrate, plants, fish, fish foods, equipment all are probably vectors for microfauna.

Fish waste contains plenty of it based on how they pick at the substrate, sides, and decorations they likely have it in them from the wild or another system they were in before they got to yours. 

Also my fingers are too giant for my phone so had to fix the typos. Sorry about that 🙂

Edited July 16, 2021 by mountaintoppufferkeeper