Aquatic plants as food
Explainer · Last reviewed 2026-08-12
Submerged and emergent higher plants — the food of the small number of genuinely herbivorous fish, and the reason a few of them can reshape a water.
A supporting record, not a fishing profile
This page is here so FishingHQ can describe a biological relationship accurately — usually because a fish covered elsewhere on the site feeds on this. It covers what it is, where it lives and the evidence behind that relationship, and deliberately nothing about methods, bait or tackle. Its presence here is not a statement that anybody fishes for it.
Herbivory is rare among fish relative to its prevalence in land vertebrates, and where it occurs it demands a specialised gut. Plant cell walls are difficult to break down, so a herbivorous fish typically has a very long intestine, a grinding mechanism of some kind, and a rate of intake that looks extraordinary beside that of a predator.
The grass carp is the clearest example in this catalogue: an adult consumes submerged and emergent vegetation in quantities that are large relative to its own body weight every day, precisely because it extracts energy from that material inefficiently. That inefficiency is why a modest number of fish can strip a water, and it is why the species is used deliberately as a vegetation control agent in some jurisdictions and prohibited in others.
The scope of this record is vascular aquatic plants: submerged macrophytes, emergent vegetation and terrestrial plant material that falls onto the water and is eaten. It does not cover algae, which are not plants in the relevant sense and are covered separately, and it does not cover the seeds and fruit that omnivorous fish take incidentally.
It is a `consumes` object rather than a `preys_on` one. Nothing here is hunted.
Where to go next
Fish this applies to
What these connections rest on (1)
Scientific evidence — 1 connection
Supported by peer-reviewed research or fisheries science. The sources are listed and can be checked.
Grass carp
Recorded diet evidence identifies submerged and emergent aquatic macrophytes as food for this species, at group level rather than as a named organism. The edge uses `consumes` rather than `preys_on` because nothing here is hunted, and it points at the category record so the granularity is visible.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: Food items recorded for this species, given as submerged and emergent aquatic macrophytes.States this directlyPassage read and verified
- FAO Species Identification Guides for Fishery Purposes and the FAO Species Catalogues — Food and Agriculture Organization of the United Nations (Scientific institute)Relied on for: Species account describing this species' feeding, recorded as submerged and emergent aquatic macrophytes.Background and mechanism onlyCitation checked — the work exists and is described correctly
More explainer
Not related to this page — just the rest of the section, because this record connects to very little and a short page should still lead somewhere.
Check the rules before you fish
Fishing laws, bylaws, access rules, seasons, bait restrictions and permitted methods vary by location and can change. Check the current rules from the relevant authority and the water you intend to fish before fishing.
Check with:
- Current national or regional law for where you are fishing
- Current local bylaws
- The relevant fisheries authority
- The landowner, club or fishery whose water it is
- Any restrictions specific to the species or the method you intend to use
Sources for this page
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: Recorded food items for the species this category is cited for, at the granularity the database records them.States this directlyPassage read and verified
- FAO Species Identification Guides for Fishery Purposes and the FAO Species Catalogues — Food and Agriculture Organization of the United Nations (Scientific institute)Relied on for: Species accounts describing feeding, given as food category or broad taxon where that is what the account states.States this directlyCitation checked — the work exists and is described correctly
How FishingHQ labels evidence is explained in the evidence policy.