Im using good old human probiotics. The trick is not to use much. Each cap has millions and millions of cells. The fish can be over dosed easily. You don't need much. In studies anything over 254ppm can kill. Probiotics are beneficial up to about 64 ppm. You need even less to get the cells into the fish guts. It can be added directly to the water or added to mw culture. Study shows it most benefit at the earliest stages right after hatching. There are many stains of probiotic bacteria. The ones approved for humans are generally very harmless, humans are very sensitive you know. The concept is simple fight the bad bacteria with the good. Lactobacillus rhamnosus is cited in many studies re fish so that is what Im using as well as 4 other strains. My source is Webber Complete Probiotic in capsules. Please note I do not want to give bad info or be responsible for someone overdosing their fish. I part of a study be done by an actual smart person with a phd. What Im doing as just a backyard breeder is helping provide some data. I may make a post in the future re probiotics with more detail an links. In any event there is enough evidence already to say they hold great promise for aquarists and many commercial fish farms and hatcheries use them already for production and disease prevention.
That is the key question right now and what I am working on. It is why I don't have quality dosing recommendations just yet. If 1 cap is enough to dose a 200lb man for 1 day how much for such tiny fry? Then you have to calculate water volume ect. Many variables from what I can tell. Sprinkle a tiny bit 1/10 of a cap in the mw culture for first feed. The rate im using is 1 cap per 10 days and it is pre diluted in pure water before going in the tank.
An easier way to get the probiotics in a dosed manner could be to try a product like this already on the market for Flowerhorns and crushing if needed. I would expect to see a probiotic betta specific food on the market soon.
You could do that Clayton. However if I were you I would wait and see the results of what Im doing and if the dose Im using ends up benefiting or harming the fish. It is too early to draw conclusions at this point imo. This is somewhat experimental and I would not want to be responsible for harming your or anyone else fry.
The best thing you can do to get good growth is
Live Foods. MW NHBBS BW Several small feeds per day vs 1 large feed.
Pristine water. Frequent water exchange and very slowly in and out but only after 10 days at earliest. Also keeps stunt homones to a minimum.
Live Plants. Infusoria and micros that comes with duckweed java moss ect right after hatching.
A clean bottom. I use a turkey baster when the fry are big enough to be avoid being sucked up by clumsy me. Getting the waste out keeps bacteria to a minimum.
No over crowding. A large spawn can take up a lot of space very quickly. Have a growout tank adequate for the number of fry being raised. The more room they have to grow the better.
Ok well I'm feeding egg yolk for the smaller fry but I have bbs for the larger ones, maybe I will wait till my next spawn in about three months to give you time to know more, thank you for the help I will check back with you later:)