Separate grazing from cleanup claims: evidence dossier
This is the audit trail behind one practical guide. It keeps the linked studies, supporting authorities, named uncertainty, search trail and public changes together without copying a second bibliography.
Guide purpose: Algae identity, local grazing, detritus, biofilm, physical export and whole-system maintenance.
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Download this guide's 6 linked evidence records: CSL-JSON or RIS. Both retain every record's support and limitation notes.
This is an inventory, not a confidence score. A direct study is still limited by its animals, experimental unit, water, treatment, duration and endpoint. Record counts do not prove consensus, completeness or a universal care rule.
- Linked evidence records
- 6
- Direct Neocaridina
- 6
- Direct controlled experiments
- 6
- Supporting authorities
- 0
- Named open questions
- 1
- Public research changes
- 3
Registry reviewed 2026-08-12. Next scheduled review 2027-02-12. Read the editorial method.
Controlled experiment
Direct Neocaridina evidence
Antcliffe et al., 2026. Royal Society Open Science 13(3): 251712.
Source taxon as published: Neocaridina davidi, with Palaemon varians as a marine comparison
Study shape: Oxygen saturation was followed for mostly 48 hours in open and closed carcass containers with carcass-free controls. A separate group of freshwater carcasses was scored daily for ten days for internal and external post-mortem change.
Experimental unit: Individual adult carcass in one container: three open and five closed freshwater oxygen containers; controls were carcass-free containers but their per-condition allocation was not clearly reported. A separate 12-carcass freshwater sequence supplied daily morphology scores.
Environment: Individual euthanized adult carcasses in 20 mL closed or 100 mL open reverse-osmosis deionized freshwater at 21 C, plus a separate open-water anatomical decay sequence
Endpoints: oxygen saturation near or around the carcass, hourly oxygen change, post-mortem internal and external morphology scores.
What it can support: In the tested 20 mL closed freshwater vials, a single adult N. davidi carcass drove oxygen saturation to complete drawdown within about one day. Open 100 mL freshwater bottles remained above full anoxia but every carcass run became at least dysoxic by 48 hours. Separate daily scoring showed rapid internal tissue opacity before major external collapse.
What it cannot support: The one-carcass-per-20-or-100-mL reverse-osmosis-water systems had no filter, substrate, plants, aeration, scavengers or living tankmates and cannot be scaled to a home aquarium, a tank-wide oxygen prediction or a removal deadline. Oxygen was reported as percent saturation and measured locally or in the tiny vial, not as aquarium mg/L. Freshwater oxygen groups were small, with three open and five closed containers, control allocation was unclear, oxygen and anatomy sequences used different euthanasia methods, and the work did not measure disease transmission, tankmate outcomes or cause of death. Clove oil and magnesium chloride methods are not home euthanasia protocols.
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Controlled experiment
Direct Neocaridina evidence
Viau et al., 2020. Aquaculture Research 51: 3847-3864.
Source taxon as published: Neocaridina davidi
Study shape: The full life cycle and juvenile outcomes were followed while comparing conditioned artificial substrates.
Experimental unit: Substrate treatment culture unit
Environment: Designed laboratory biofilm culture across substrate treatments
Endpoints: juvenile survival, growth, biomass, biochemical reserves, reproduction.
What it can support: The tested biofilm community supported the life cycle and substrate treatment changed juvenile outcomes.
What it cannot support: It does not establish that any home-aquarium film is complete food or that tank age measures grazing value.
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Controlled experiment
Direct Neocaridina evidence
Kong et al., 2019. Hydrobiologia 827: 75-87.
Source taxon as published: River-collected Neocaridina denticulata, retained as published
Study shape: Four treatments separated litter alone, direct shrimp contact with feces falling away, feces contact without direct shrimp contact, and shrimp plus litter plus feces together. Each shrimp unit held eight animals and 3 g of air-dried cattail litter. Four independently prepared buckets represented each treatment at each 35-day destructive harvest, for 64 buckets total. Filtered river water was replaced weekly.
Experimental unit: Four-litre bucket, with four independent buckets per treatment and harvest time; the paper describes destructive treatment-by-time units but reports date as a repeated factor without explaining how repeated units were linked
Environment: Sixty-four aerated four-litre river-water microcosms in an environmental chamber set to 20 C, with measured water varying from 20 to 25 C during 140 days
Endpoints: cumulative litter dry-mass loss, decomposition coefficient, interval mass loss, leaf-associated extracellular enzyme activities, pH, chemical oxygen demand, ammonium nitrogen, nitrate nitrogen, total nitrogen, total phosphorus.
What it can support: After 140 days, cumulative litter mass loss was 51.7 percent in litter-only controls, 83.4 percent where shrimp contacted litter but feces fell away, 57.8 percent where feces contacted litter without shrimp contact, and 84.5 percent where shrimp, litter and feces remained together. The treatment contrasts support faster breakdown when shrimp had direct access under this microcosm protocol; water chemistry and enzyme responses also differed among treatments.
What it cannot support: Litter mass loss is not measured ingestion. Direct shrimp access combines grazing on leaf tissue or associated microbes, fragmentation and physical disturbance, while the reported grazing and feces shares were derived from treatment contrasts rather than measured intake. The experiment used one river population, one cattail preparation, eight shrimp in four litres and filtered river water replaced weekly, which the discussion says helped provide food; no formulated-food baseline was described. Reported zero mortality does not establish dietary adequacy because growth, condition, molting, reproduction and health were not measured. The paper switches between Typha angustifolia and Typha orientalis in treatment text and figure material, gives conflicting one-week versus one-to-two-day animal holding descriptions, does not report random allocation, lacks an obvious sham-mesh control, and does not reconcile destructive harvest with repeated-measures analysis. It also labels P values above 0.05 through 0.10 as biologically significant but noisy. The result does not recommend cattail, catappa or alder, establish a ration or replacement interval, prove a complete diet, or promise home-aquarium water safety.
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Controlled experiment
Direct Neocaridina evidence
Ye et al., 2019. Knowledge and Management of Aquatic Ecosystems 420: 32.
Source taxon as published: Neocaridina denticulata sinensis, retained as published
Study shape: Four mesocosms received eight shrimp each and four had no shrimp. Each began with about 29 g fresh plant mass. Water and leaf periphyton were sampled after one week and every two weeks thereafter for 119 days, then final plant fresh mass was used to calculate relative growth rate.
Experimental unit: Seventy-five-litre mesocosm, with four independently assigned mesocosms per shrimp treatment
Environment: Eight outdoor 75-litre polyethylene mesocosms with sediment, tap water and Vallisneria denseserrulata; water temperature varied from 17 to 30 C
Endpoints: leaf periphyton chlorophyll a, water-column chlorophyll a, total and dissolved nitrogen, total and dissolved phosphorus, Vallisneria relative growth rate.
What it can support: Under this outdoor mesocosm protocol, shrimp presence was associated with lower mean leaf-periphyton chlorophyll a and higher Vallisneria relative growth rate, while water-column chlorophyll a, total nitrogen and total phosphorus were higher than in no-shrimp mesocosms.
What it cannot support: The experiment used one plant species, sediment, naturally varying 17 to 30 C water and a fixed density of eight shrimp per mesocosm. It did not identify a home-aquarium algae, test a stocking gradient, measure nutrient export or establish a cleaning rate. Repeatedly removing three leaves per tank changed plant material over time, periphyton chlorophyll received no pheophytin correction, water-column chlorophyll units conflict between the results text and figure, and only four mesocosms per treatment constrain precision. The result cannot justify introducing or releasing shrimp for restoration outside native, permitted and professionally assessed systems.
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Controlled experiment
Direct Neocaridina evidence
Groendahl and Fink, 2017. Scientific Reports 7: 44869.
Source taxon as published: Neocaridina davidi within a three-grazer freshwater model
Study shape: One to three grazer species were assigned to defined algal communities for three days, then grazer richness and phosphorus were combined in a one-week factorial experiment.
Experimental unit: Three-hundred-millilitre flask, with six to eight usable replicates depending on comparison
Environment: Laboratory flasks containing defined green-algal communities at 20 C
Endpoints: algal cell count, algal biovolume, algal species richness, algal diversity and evenness.
What it can support: Neocaridina davidi reduced several tested algae and showed a relative preference for Closterium moniliferum in the three-day model.
What it cannot support: The defined short flask experiment does not establish hair-algae control, a cleaning rate, a complete diet or whole-aquarium nutrient export.
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Controlled experiment
Direct Neocaridina evidence
Weber and Traunspurger, 2016. Limnologica 59: 155-161.
Source taxon as published: Neocaridina davidi
Study shape: Shrimp and comparison microcosms were sampled repeatedly, followed by endpoint stomach-content examination of 40 shrimp.
Experimental unit: Model ecosystem for community effects and individual stomach for content observations
Environment: Forty-two-day freshwater model ecosystems with repeated community sampling
Endpoints: meiofaunal density, biomass, secondary production, community structure, stomach contents.
What it can support: Shrimp changed measured meiofaunal assemblages, and stomachs contained detritus, algae and several meiofaunal groups.
What it cannot support: The study did not test fish feces, aquarium sanitation, nutrient export, named pest danger or a whole-tank algae-clearance rate.
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