Culturing Green Water and Micro-crustaceans

A bunch of fish and inverts feed on green water in their youngest days. Given the recent interest in this subject, I wanted to share my latest experience in starting a green water and infusoria culture.

Yes, this one was on purpose. Not a tank mess up that resulted in a green water algae outbreak lol. I raise scuds, copepods, and daphnia as live food for some of my fish that won't eat anything prepared. From what I've been seeing the scuds eat decaying plant matter, and the micro-crustaceans eat micro-algae (green water algae).

My culture container is a 1 gallon tank that I used as a spare, a grow out tank for a baby betta, etc etc, then sterilized to be used as my primary culture container. It gets minimal light, all natural or reflected from a nearby planted tank.

In order to start the culture, I set the tank up like this:
~Handful of potting soil, capped with black sand (this just happens to be what I had on hand. any sand will work. I don't suggest gravel for culturing scuds as you're likely to lose them between the rocks).

~Tossed in some moneywort, left floating

~1 cup water from a 100% healthy planted tank

~Declorinated tap water (I use RO because I'm not sure the little bugs could survive my tap water with its high copper content. most tap water would probably be sufficient though) to fill the rest of the tank.

~Plant clippings (only use leaves or stems that are decaying for this) from a 100% healthy tank

~Then I added my starter cultures. Starter cultures for these critters will already contain some green water algae. Algae wafers can be added as food until you have a good culture going. I didn't find this necessary due to the fact that I used potting soil, and no live plants survived with the light the tank gets. I had a solid green water culture going after a week. Now I have full on infusoria.

It should be noted that if you choose to culture copepods, you should only get cultures from a fishless system, as copepods are able to carry parasitic nematodes (camallanus worms) and pass them on to your fish. I got my starter cultures from a scientific supply company that raises each crustacean in its own container for easy identification and separation for sale.

I have actually witnessed the scuds mating, so I know they're getting plenty of food from this setup. Can't say I've seen anything else reproducing, but I know I have more of the little guys now than I did a few weeks ago, so someone must be making babies lol.

 

I have little experience in culturing green water, or the zooplankton that goes with it, so forgive me if this question is naive.
Why did you introduce the the moneywort, and why did you limit the light to such an extent?
Also, would you happen to have the name of the supply house that you used handy, by chance?
Thx--rick

 

No problem, rick!

I introduced the moneywort because it was starting to look a little hinky in my tank, so I thought it might help with the culture. I also wasn't sure exactly what the micro-crustaceans ate, especially the scuds, and my googling turned up little on the subject. I suspected they would feed on algae and decaying plant matter, but wanted a live plant as well, just in case.

Anyway, the moneywort is dying and basically ended up just being food for them.

As for the light, I originally intended to harvest them on one of my breeding tanks' tables, where the culture would get a bit of natural light. The light for this tank is incandescent and wouldn't grow plants anyway, so I just left it without. It's next to a tank with a plant light and that seems to be enough to keep the green water going, along with plenty of decaying leaves and such. In the end, lack of light was just a fluke but it seems to be working fine on ambient light.

 

I know people are quiet successful producing healthy green water in ponds, but have problems in tanks, green water is very helpful in controlling nitrates. From what I recall, some start with a small dose of green water from outdoors to seed their indoor tanks.

 

I know people are quiet successful producing healthy green water in ponds, but have problems in tanks, green water is very helpful in controlling nitrates. From what I recall, some start with a small dose of green water from outdoors to seed their indoor tanks.

I'm just too paranoid about my tanks to do that. I collected a few plants from a local waterway that look exactly like cabomba (odd because of where I live... but whatever) and quarantined them, but was still too paranoid to put them in my tanks 3 weeks later. Even after a rubbing alcohol bath... lol!

I figure with enough excess nutrients in the water, the algae will come eventually... I got it pretty fast in this culture tank, I think because of the potting soil I used.

 

one thing to add about green water is daily swings in alkalinity and pH are going to happen If the algae density is high enough and there is limited buffering capacity, the environment is really tough on fish.

June, ive also heard of some using rain water to get their green water culture kick started.

 

Riv, I somehow managed to miss your post before, but I needed to update this thread anyway.

The culture tank should not contain any fish. Not only will they eat the culture, but the culture will not be "clean" if it's exposed to fish. This is a 1 gallon container with nothing but dirt, plants, and algae growing in it. And of course the little crusties!

I actually neglected this culture tank, got distracted conditioning some of my fish to spawn, rearranging tanks for fish that had decided they would try to spawn even though there was no reason to, and various other projects.

I had planned to add an airstone at some point, but again this was left undone while I neglected the tank.

Well I'm proud to say, that somehow, the culture is not only alive, it's thriving! I shook the tank earlier today to see if I could save any scuds, and there was this explosion of movement! A bunch of scuds have survived and apparently bred, and the copepod population is massive now, which means I'll be harvesting some to give my fry once they become free-swimming.

Given the success with my complete neglect of the tank, I'm no longer planning on changing anything except adding sanitized plant clippings when I trim my tanks. The green water culture continues strong as well as the crusties, so there's plenty of food. Any swings in water parameters haven't bothered the critters apparently. The pH in this container is quite low, as I used RO water, fearing the high copper content in my tap water might be lethal to the scuds. I have no idea if that's accurate, but better safe than sorry, right?

Edit: I actually saw a baby scud! I was attempting to scoop out some of the copepods to feed the fry I'm expecting in a few days (the adult fish aren't likely to eat them so I was just going to put them in the tank) and I caught a tiny little white shrimp baby!

So I had to put the scoop back.... lol! Yes apparently I feel bad feeding baby scuds to my fish...

So I'll probably leave the container alone for another few weeks, let the population grow a bit, and just feed the fry something else for now

 

You lady are a Fish Masta!

 

Haha it's fun when my accidents and mistakes end up working in my favor!