Another Hewbie Update!

[AydenLincoln]

Even with all those consultations, the core logic still has a few major gaps when applied to a single pet fish in a closed aquarium.

First, commercial farming data doesn't equal pet care. You admitted yourself that there is no support for common saltwater aquarium fish, and extrapolating data from mass aquaculture (where the goal is herd harvest times and profit margins for thousands of fish in open or high-flow systems) to a single pet fish in a closed glass tank is a massive leap.

Second, efficiency is useless without fuel. Probiotics improve the Feed Conversion Ratio (FCR), meaning they help an animal process food more efficiently, but efficiency doesn't create calories out of thin air. If the puffer isn't taking in enough raw food and calories to begin with, optimizing its digestion won't make it gain weight.

Third, guessing that an "anecdotal experiment" with an industrial chemical will rebuild his gut microbiome is a gamble. While antibiotics do strip gut flora, the probiotic you're using (FeedTreat) relies on specific Bacillus strains engineered for commercial aquaculture. You have no way of knowing if these specific strains are even capable of colonizing a porcupine puffer’s native gut microbiome, or if they just pass right through as transient waste.
Fourth, there is a serious dosing nightmare and scale problem. This product is meant to be mixed by the kilogram of commercial feed, and I highly doubt you have a specialized laboratory micro-scale precise enough to accurately scale down an industrial aquaculture dose for a single portion of food. Eyeballing it means you are probably overdosing it.
Lastly, "hoping for a push" with an incorrectly dosed industrial product can actively harm his recovery. Because this product is packed with billions of bacterial spores per gram designed for large-scale systems, overdosing within a closed home aquarium can cause a severe bacterial bloom, cloud the water, and deplete dissolved oxygen. Subjecting a weak, slow-healing fish to that sudden environmental shock and water fouling will actively stress him instead of promoting healing or recovery.

In summary, I still think your efforts are commendable, but the logic is flawed due to the reasons I mentioned above. You previously mentioned that "Similar to humans or mammals antibiotics will always have a risk of killing good and bad". When antibiotics are prescribed to humans, they are rarely advised to take probiotics afterwards because they aren't necessary for recovery post-treatment.

I have a rebuttal for that. One these bacteria from my understanding and what the manufacturer told me don’t directly colonize inside a fish’s internal environment directly at least long term rather they promote healing and promotion of good gut bacteria. The reason I am doing it is because it was targeting an internal infection directly inside his intestines and swim bladder. In other words his gut microbiome. In humans if you have an infection that is stomach related or intestine related or another health condition probiotics and prebiotics are recommended to recolonize anything meds may unintentionally kill. But the same goes for nearly any antibiotic it is not something that may always be told to a patient but the research in humans supports it but it just depends on antibiotic used and condition treated. That being said you do happen to get this in the foods you eat especially yogurts one of the reasons it is not always necessary to directly take a pill form of them. Some research in humans actually supports taking it with them rather than after. But that doesn’t mean it is absolutely necessary to do it just means doing it can help healing in humans and other gut/digestive issues. But I am not comparing it as a whole because there are so many other factors. My comments were simply stating because it is logical that antibiotics can do more harm than good in all living things they are used for. All this being said neither one of us are doctors or aquatic veterinarians or researchers so I am going to leave it at that and that I do see your points!