Aufwuchs eaters, aren’t vegetarians… the Hillstream loaches I have aren’t vegetarian

Mine, love Tubeflex worms, and brine shrimp, as well as Ultra Fresh micro pellets…they get a balanced diet of micro proteins and algae… tonight I cut some freeze dried tubeflex cubes into pencil lead sized strips, and the whole tank is going bonkers, same when I feed frozen brine cubes…

Repashi soilient green, is supposed to best mimic Aufwuchs… and those ingredients look like this… ( note the proteins, as well as veggies )

“Chlorella Algae, Spirulina Algae, Whole Krill Meal, Whole Squid Meal, Whole Sardine Meal, Alfalfa Leaf Meal, Whole Anchovy Meal, Germinated Brown Rice Protein Concentrate, Pea Protein Isolate, Dried Brewers Yeast, Stabilized Rice Bran, Dried Kelp, Carrageenan Algae, Konjac, Carob Bean Gum, Schizochytrium Algae, Calcium Carbonate, Dicalcium Phosphate, Taurine, Potassium Citrate, Calcium Propionate, Phaffia Rhodozyma Yeast, Paprika Extract, Calendula Flower Powder, Marigold Flower Extract, Rose Hips Powder, Turmeric Root Powder, Malic Acid, Sodium Chloride, Canthaxanthin, Potassium Sorbate, Magnesium Gluconate, Lecithin, Rosemary Extract and Mixed Tocopherols (as preservatives), Vitamins (Vitamin A Supplement, Vitamin D Supplement, Choline Chloride, Ascorbic Acid, Vitamin E Supplement, Niacin, Beta Carotene, Pantothenic Acid, Riboflavin, Pyridoxine Hydrochloride, Thiamine Mononitrate, Menadione Sodium Bisulfite Complex, Folic Acid, Biotin, Vitamin B-12 Supplement).”

I don't feed tubifex in any form to any fish anymore. They breed in sewage, eww! I also don't like freeze dried foods much. Too hard to rehydrate so they sink (looking at you blackworms & brine shrimp, & my beloved bottom fish).

I feed Repashy Soylent Green to my sewellia hillstreams, but they will eat some flake & pellets. My F1 sewellias were raised on Repashy aufwuchs & they breed at least once/year. It's only a small bother to mix it up & freeze the leftovers. I do 1:3 Pashy to water, so not as expensive as it might seem. I usually freeze the unused powder too, I only have 1 tank that wants it, but 2 that will eat it.

I could cook a spaghetti bolognase for a vegetarian friend with beef mince, and tell them it's made with qourn. They could eat it not knowing. They are still a vegetarian. A lot of fish will eat anything put in front of them. Mbuna and frozen bloodworm for example. The joy of a fish when it gets food is not always a sign that the food in question is suitable for them.

Vegetarian, herbivore - it matters but to me, the key issue is fibre (fiber in the US). Insectivores need roughage as they devour entire bugs, hard parts and all. They don't carve any Christmas turkeys.

Herbivores eat whatever organisms are in the plant matter they prefer, along with the plants.

Both groups need roughage and fibre for their gut health.

It isn't preference - they have different digestive systems for extracting what they need from the foods, and we have to respect that. The first thing I look at in any prepared food is the fibre content, and some of the foods have disturbingly low percentages.

Guess my point being, Aufwuchs ( wild algae ), is so much more than the sterile algae that grows in our tanks… there are so many small critters, that get eaten also in wild natural algae… @GaryE … brings up a good point with fiber, but I’m going to call it “roughage” , as exoskeletons, and shells consumed from in real Aufwuchs, can’t be discounted, and is generally not available in our sterile aquarium algae… for example, I dust up Bug Bites, and a few other foods, so that dust supplements my bio film, and as such, my fish seem to be thriving… I also have a dedicated coffee bean grinder, to dust up dried meal worms, and actual Black Soldier fly larvae…

I’m between fly larvae right now, I had a big bag, and got mice into them, so the bag got tossed ( who knew mice would go out of their way to eat larvae??? )… we have to set a trap line, every fall, with a 100 year old farm house…
But believe the roughage, contributes to digestive health…

I do the same for all my sucker mouth fish, from my plecos, to my zebra Oto’s, and even my giant Oto’s ( Hypoptopoma thoracatum )

I've mentioned this in ancient threads, but I remember watching magnificent mollies in a Yucatan cenote. The water was crystal clear and the sun was shinning on a wall of aufwuchs that was a few cm deep. Hundreds of mexicana mollies were picking through the algae. They didn't seem to be eating it directly - they seemed more interested in what was in it.

So as @Magnum Man says, we should aim for what's in there, as well as for the algaes that fish eat with it. There are things like Otoconclus that like the algae more, and every fish is different, but I do what he does, without mice at the moment.