Can you explain the use of yeast in a fry-tank set up?

[Mmathis]

I won't go into a lot of detail, because frankly, I was reading posts and conversations and had no idea what the relationships were. This was on another forum and the topic was raising fry. They were talking back & forth about raising infusoria and brine shrimp to feed very young fry and adding them [the water] to the fry tank, etc. I was following that OK, but then they started talking about adding "yeast" to the fry tank every few days and something about keeping the fry tank clean. And that's where I was losing it. I was never able to figure out WHAT the yeast was for. Was it for the infusoria to eat, or what? Then there was some mention of adding "yeast" and keeping algae down......

Can someone expain what they might have been talking about?

And, no, I'm not raising fry -- it was just a post that caught my attention and got me curious about the different ways people raise their fry. But I've never read about yeast......except for making beer or breads......

 

[Meyer Jordan]

Yeast has for some time been used in aquaculture as food supplement, replacing fish meal supplies which are becoming increasingly scarce. Yeast provides the nutritional value of fish meal with the additional benefit of serving as a prebiotic. Yeast promotes the digestive process in fish by stimulating the growth of the beneficial gut bacteria, enabling more efficient digestion. Yeast also has been shown to increase and strengthen the fish's resistance to certain pathogens such as Aeromonas hydrophila.
Brewer's yeast may create an inhibiting effect on the growth of algae because of its nutritional composition...55% protein and 45% carbohydrate. This additional sugar (carbohydrate) that is added by the act of fish meal replacement will promote bacterial growth which, in turn, will compete with algae for the available Carbon in the water.
This is a somewhat simplified explanation but I hope it answers your questions.

 

[Mmathis]

@Meyer Jordan Thanks! Yes, it sort of helps..... So, the fry are eating the yeast? And that's good for them....... Is there an age in fry development [ie -- the actual size of the fish as well as it's age] where this works best?

They didn't specify whether this was baker's yeast or brewer's yeast that they were talking about. So still trying to figure out if it was for nutritional reasons or something else -- they kept commenting, like, "add the yeast, and in so-many days, the tank will be clean....."

So, what would happen if you added yeast to the pond......? Just saying......

I'll see if I can track down where I found this. Maybe that would help.

 

[Meyer Jordan]

So, what would happen if you added yeast to the pond......? Just saying......

This could be treading on dangerous ground if not closely monitored. This is basically he same discussion as the one about adding Vodka.
The addition of any simple sugar will stimulate bacterial growth which, in turn, places a greater demand on the Oxygen content of the water column.
In an aquaculture facility, almost everything is computer controlled and monitored 24/7/365. Simple sugars are sometimes added to promote the growth of 'Floc', which are nothing more than free-floating bacterial colonies which serve as an alternate diet to the farmed fish. Pure Oxygen is available for injection into the water column when the sugar is added or if the DO level begins to drop too low. Garden ponds do not have the luxury of high tech cutting edge equipment.

 

[Mmathis]

@Meyer Jordan Am sending you a PM, but give me a few minutes to write and proof it.