so, what are all the critters found in a mature tank, and if they aren’t added, where do they come from???

[Magnum Man]

talking all the micro critters that seem to be in a nicely matured tank… we add dead leaves for critters to grow on as fish fry food, so, I’m mostly talking about the smaller stuff… seed shrimp and smaller… and if you have a growing population of fish at the fry stage, can these critters thrive in a tank full of fry, or do they need to be added regularly???

I’ve been really happy with the dwarf crays I’ve added recently… the word is still out, on weather they can thrive ( reproduce ) in a tank full of fish???

maybe these larger critters would reduce the population of the smaller???

right now I’m using a few larger tanks, that had tilapia in previously, and being a fish that produces a lot of waste, there has been lots of mulm I vacuum out weekly… I’m guessing that’s a food source for most of these small critters, and perhaps, a lot of fish fry as well???, and I may be sucking out lots of the micro fauna, when I vacuum substrate ( soon it will be reduced to a level, that I’ll just do water changes ) and have the sponge filters and hang on back mechanical filters, as the substrate is just a shallow layer of river pebbles…

thoughts, and or your experience with micro fauna???

 

[squirley]

I believe that flying insects can infiltrate aquariums. I have never observed it though.

 

[Uberhoust]

A lot of the organisms that can end up in your tank come from eggs, cysts, etc. that come in from plants, wood, leaves for tannin etc. When I don't add outside materials to a tank, and dip all the plants and hard scape in a bleach solution the numbers of other organisms such as seed shrimp are generally absent. When I relax that rule a bit I end up with all sorts of different items in the tank. I also noted that the fish you keep also affect what you find, some fish are much more likely to eat that seed shrimp before you every see it. When keeping a shrimp tank I noticed a lot more unique critters in the tank.

 

[Rusty_Shackleford]

Where do the bacteria and algae come from when we fill a tank?
Floating in the ether.....

 

[GaryE]

Everything we add has a bioload, including tapwater. Chlorination kills many pathogens, but water's water, and it carries microscopic life. It's been years since I saw seed shrimp. Non tissue culture plants add, stuff is airborne, and the eggs and such of bugs come in.

I figure we're constantly breathing in beasties.

Bugs bring bugs, not just breezes. Your hands are probably a good source. The fish you add have gutloads. Houseplants and cats and dogs near the tank add in, as do other people.