What are some examples of fish that are herbivorous in the wild (i.e., not carnivorous or omnivorous)? Do any eat kelp?
One good example is the Grass Carp. Tropical reef fish that are largely herbivorous are some parrotfish and damselfish.
There are lots of aquarium fish that are algae eaters. One of the best known is the algae eating catfish Plecostomus.
In the Amazon a common herbivore is the Pacu, sometimes called the “vegetarian piranha.”
I was going to exclude algae-eaters in the OP, but I didn’t want someone pointing out that giant kelp is an algae. What I was getting at were which fish eat kelp, eel grass, etc.; and not ‘algae’ algae.
The grass carp looks like an example of what I was looking for, as it eats ‘aquatic weeds’. Thanks for that.
I think there are very few. Fish are very opportunistic. My first reaction was to say carps but, on second thought, it’s not true. They’ll eat midges and nymphs when the opportunity presents itself. Popular baits (although it isn’t as successful as bread or corn) for carp are different types of worms, nightcrawlers, red worms, maggots etc.
My friend has caught a Pacu while fishing for catfish with a piece hot dog.
I guess I should ask, by “wild” do you mean their native habitat or anywhere that they don’t get hand fed?
I’m not sure about Plecos but Chinese Algae Eaters occasionally eat smaller fish too.
Yes.
There are lots, actually, if you consider fish that are mainly herbivorous. Of course, many fish that eat mainly vegetable matter sometimes eat meat. But that’s true of many other kinds of mainly herbivorous animals.
To which one? They’re not both the same. Native fish have always been in a body of water. Wild fish are fish that were once put into a body of water but are now living in there on their own. And I guess fish actively fed are pets or something.
Yeah, I was just stating that there probably aren’t a lot of 100% veggies only herbivore fish.
Yes to both. Or either.
I have always had at least one Plecostomus in any fish tank and have never had them eat live fish. However, they’ll eat just about anything on the bottom or sides of the tank, including regular fish food, dead fish and fish eggs.
Mullet are principally herbivores. That is not to say that smaller fish and marine animals do not get eaten as the mullet feeds on plants, but the mullet will not seek out non-plants as food. Growing up in coastal Florida,I learned that it was common knowledge that mullet would only occasionally bite a baited hook, and then ONLY if the hook was baited with dough or bread. Mullet were typically caught in cast nets or snagged as one drew a treble hook through a school. The nets were the most common and reliable method.
Another interesting fact is that mullet have a gizzard like a fowl.
Very few fish are obligate herbivores, especially when you take into account that larval fish will eat plankton or benthos and be none too picky about whether its zooplankton or phytoplankton. But as Colibri and others have pointed out, plenty eat both plant/algal and animal material.
When the kelp is young and tender, plenty of the scraping fishes will eat the kelp, and just about any plankivorous fish will eat the spores in the water column. If you’re talking about browsing on the blade, stipe, or holdfasts of adult kelp, not many fish can eat that. Adult eelgrass also doesn’t attract a lot of browsing fish.
Opaleyes are one of the few fish I can think of that will take bites directly out of adult kelp blades, and they’re not primarily herbivores - they’re omnivores.
Most of the plant material in estuaries and kelp forests dies uneaten and contributes to a rich detritus layer which feeds invertebrates and bacteria, and fish feed upon those detritivores.
I’m beginning to see why I can’t think of any piscatorial herbivores.
But yes, I’m talking about ‘plants’ in the way we usually think of ‘plants’ – such as kelp, eel grass, and other ‘macro’ plants; as opposed to ‘fuzzy’ algae and such.
So I guess the OP can be modified to ask which fish browse on the ‘macro’ plants, even if they are not herbivores.
Thanks for the answers so far!