Fingers crossed for the gulpers - and everyone else, too, of course!
Really hope things have been improving! I’ve read through the whole journey and watched lots of your YouTube videos. I’m interested in setting up a gulper tank and really appreciate your hard work and dedication you have for yours. So much good information that I haven’t seen elsewhere. Slightly off topic but I’m curious. Would they do well in a tank with decor (wood, rocks) and sand substrate? I assume all of the bare tank setups are for easier tank maintenance and to better observe the fish. Would they scratch themselves on driftwood and sticks or harm themselves from inhaling sand and leaf litter? Hoping to create a natural display type tank
I know you've mentioned that you're feeding herring - apparently herring, anchovies and related fish contain thiaminase, enough to the point that vitamin B deficiencies have been noted in salmonid populations in the Baltic that feed primarily on herring and alewife consuming populations in the Great Lakes.
Thiaminase
www.wetwebmedia.com
This is a pretty good read on thiaminase and predatory fish nutrition. Apparently prawns/tiger shrimp also contain thiaminase, and those are 2 very popular food items for most North American predatory fish keepers.
Is it possible that we see plenty of these predators grow larger/live longer in Asia because of different market fish/invert availability, with Asia having more access to a wider variety of thiaminase free options?
However, this is not a complete story and there are controversies. For one instance, Dr. Keller the main vet of the Tennessee Aquarium tells us thiaminase forms in animals after / during death (in all fish it seems he is saying) and its presence and amount depend on the exact manner of death and he recommends to feed live if one really wanted to avoid thiaminase worries. They at the Tennessee Aquarium cannot feed all their predators live so they deposit precise amounts of Thiamine E paste into every frozen/thawed fish they feed to their predators.
You got my explanation right. Yes, super bizarre to me too but I am open to new knowledge, as I said so long it is backed by trustworthy science, not expert guessing. A highly complex protein that has a complex supramolecular structure (a long molecule, amino-acid polymer folded intricately), an enzyme, an anti-nutrient, which the organism has no use for (and if the organism had this enzyme, the enzyme would likely kill it) but has the precursor, forms inside the organism during/after death and the details of death - time, temp, who knows what else make it happen or not.
That wouldn't explain the thiamine deficiency in the Great Lakes population in particular that subsist primarily on alewife versus other piscivorous populations that don't have this issue when consuming a larger variety of fish. Could it be possible that it's present in in different species of fish in varying amounts and, upon death and the rapid breakdown of certain lipids and tissues, it is either produced in greater quantities or perhaps some other molecule breaks down with those tissues and produces another deficiency that leaves the predator more vulnerable to the effects of thiaminase? Garter snake enthusiasts often report of thiamine deficiency in specimens fed live goldfish and rosies but not in those fed livebearers which apparently don't have thiaminase. I almost never hear of anyone feeding goldfish and rosies prekilled so I think it's a pretty safe assumption that the vast majority of cases reported in both the aquarium and herp hobbies involve live feeders.