It's interesting. We have a strange collective approach to sick fish. When I was in my teens, the great problems were Ich, fungus and velvet. Fungus treatments, which I now suspect were based on acriflavene, a med now considered carcinogenic for humans (extreme low risk, but) were standards on shelves.
Tetra fungi-stop was in every pet store.
Then, maybe because of the ingredients, it vanished. So did fungal diseases, from the minds of aquarists. I fell into that discussing this illness. I thought bacterial. But I'll wager a lot of what we think of as bacterial is probably fungal, as far as external infections go. It's put me on a train of thought I'll indulge myself by sharing. I'm always writing here not just for the one conversation, but for any new aquarists looking in.
We also stopped worrying about velvet (Oodinium), a parasite that remains very common and very destructive. I've mentioned it as a possibility to a number of disease queries, and people tend to ignore me and look for something else. They haven't even heard of it. I've seen it in stores, and it's arrived here every now and then. It likes soft water. It's actually out there, lurking and living.
Mycobacter (fish tb) makes the industry people run screaming with their hands over their ears. It has so many symptoms and is so hard to diagnose in a living fish that it's easily swept under the carpet. It's a big killer of our "disposable" fish, and is a huge threat to captive breeding programs for extinct or critically endangered species, as far those exist. But it is in the "don't mention that" category for us.
Imagine if human medicine identified four or five diseases, and thought that was it? That's where we are with aquarium treatments. It's really odd. It's a good reminder, as tough as it is for your poor fish, that fungal diseases are still out there. I'll smack myself on the side of the head for not thinking of fungus as a possibility. And then hope your fish gets through this.
You're completely right in your assessment of the hobby, I think. It does feel like there is such a narrow scope of what we keep at the forefront of our minds as hobbyists in terms of disease. There are only a handful—maybe a dozen at most—of diseases that are even talked about as "options" for what could be going wrong with a fish. And, what I have personally felt, is that even within those few diseases, the scope of how those diseases might show up is presented as rather limited.
Personally, I think I didn't give much consideration to fungus in this case because almost all of the hobbyist-focused education currently available paints "fish fungus" as something that presents as fuzzy tufts of growth. It's true that saprolegnia is probably the most common aquatic fungus that infects fish, and as far as I know, it almost always has a growth form that projects out from the body in a way that looks like fuzzy cotton. It's reasonable that education is focused on it, but surely there are more infectious fungi out there, and they are almost never considered as a possibility within hobbyist spaces. I'll definitely be re-examining some of my assumptions here, and with other diseases.
Regarding the diseases that lurk: I think people don't like to admit to themselves that potentially infectious agents live in their tanks at all. People like to believe their tanks clean and free of disease. Even the threat of illness in their tanks would be considered offensive. The implication that they aren't doing enough, that they aren't eliminating all risk, is frightening. It is the reality though. Flavobacterium, mycobacterium, oodinium, etc. are all facts of life in aquatic environments, and short of UV sterilizers, they will always be present. I think if people were more comfortable with admitting that there are risks in their tanks, there would actually be more positive effort put towards prevention. But you're right, they (especially mycobacterium) are treated as taboo. Certainly no supplier would ever admit such a risk exists within their stock.
I'll prepare the first MB bath for this fish tomorrow, and I do really hope that this is the solution I've been looking for. This poor fish has been through a lot, and has remained so chipper throughout it all.
For anyone listening (reading) in on this conversation: I recommend picking up a copy of the Exotic Animal Formulary. It's only around $50USD (surprisingly cheap for what is essentially a veterinary textbook) and it contains an extensive list of antimicrobial, antiparasitic, and anesthetic chemicals used for fish, as well as tested dosages and recommendations for use. It is NOT a diagnostic tool, but if you are going to be using a medication using your own judgement—especially an antibiotic—it's worth knowing the proper dosage for it and what method of application is best for certain treatment goals.
