PlanetCatfish.com

KG: Grains, breads and products made from them are not good sources of much of anything (except excessive empty calories) that can't be found in more nutrient dense sources of whole foods like greens, eggs, meat and the like. Grain is not a good staple for humans ...

VJ: this sounds quite foreign to my thinking but likely because I need to be educated further. You need calories from carbs. They need not be excessive if you do not over-indulge nor empty if you burn them.

In my, perhaps limited, opinion, wheat, rye, rice, maize, buckwheat, and other grains have been the staples throughout the ages and are still the staples for 2/3 of humankind who cannot afford meat and eggs and practice mostly what is described as a natural way of living.

Yes but even if you burn the calories from a bready snack away, you are still eliciting an insulin response and paving the way for cardiac inflammation and diabetes. Not that people should all religiously forsake all grains and bread, but it definitely shouldn't comprise any more of one's diet than it has to.

And fish don't exercise.

Generally speaking, each fish will need its own diet

I disagree with knifegill on human food, but that's off topic. I do however agree with him that grains and other carbonhydrates are rarely found in the water, so any valuable food will cary little of them

Still most fishkeepers feed their fish mostly, sometimes exclusively, with dead animals. Many fishes neet veggie food. Corydoras, for instance, search among the sand for food. What will they find? every now and than an animal, but very often veggie things.

Plants contain a lot of minerals and vitamins not found in other food sources. Therefore, fish which do accept veggie food - even predators - are best fed with a bit of veggie food. Obviously, true herbivors should be fed (almost) exclusively with veggie food

Update:
The little guy is doing pretty well. He managed to break off one of his antennae but it looks like it's already growing back. He doesn't come out much at all, but that's probably due to the adonis' being territorial. Oddly, he has become cavemates with a gold dust bichir (buettikoferi). Haven't seen him eat but he's not starving so my nighttime feedings must be paying off.

I'm also allowing the hardness in my 55g to wane since it's currently around 7.5 thanks to crushed coral. I've done some reading about low pH tanks and I'm going to let it drop on its own from now on. I've ordered a low range pH test kit and will watch it. But I found a couple of good articles that make an important distinction between CO2 pH and GH, KH hardness. It seems I was overly concerned about the pH swing caused by my tap water degasing. It's differences in hardness, not pH, that cause shock. And since most of my fish prefer acidic water anyway, I'm going there.