Plan water changes and top-offs: 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: Purpose, dilution, source-water preparation, top-offs, filter cleaning and change records.
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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
- 3
- Direct controlled experiments
- 3
- Supporting authorities
- 3
- Named open questions
- 1
- Public research changes
- 0
Registry reviewed 2026-08-12. Next scheduled review 2027-02-12. Read the editorial method.
System observation or method study
Adjacent aquarium-system evidence
McKnight and Neufeld, 2024. Applied and Environmental Microbiology 90(7): e00104-24.
Source taxon as published: Freshwater aquarium microbial communities, not a Neocaridina animal experiment
Study shape: Microbial genes and community composition were surveyed across aquarium biofilters.
Experimental unit: Sampled aquarium biofilter
Environment: Thirty-eight freshwater aquarium biofilters
Endpoints: comammox genes, relative abundance, community composition.
What it can support: Complete ammonia-oxidizing Nitrospira occurred widely in the sampled biofilters.
What it cannot support: Detection and relative abundance do not measure a tank workload, prove full commissioning or establish an animal-safe concentration.
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Controlled experiment
Direct Neocaridina evidence
Melo, 2023. Doctoral thesis, Federal University of Minas Gerais.
Source taxon as published: Neocaridina davidi
Study shape: Separate total-ammonia and nitrite experiments used a control plus five treatments, two vessels per treatment and ten juveniles per vessel.
Experimental unit: Exposure vessel, not each shrimp
Environment: Renewed 96-hour acute laboratory exposures at about 25 C
Endpoints: 96-hour mortality, median lethal estimates, gill histology.
What it can support: Direct acute juvenile ammonia and nitrite exposure-response estimates with stated nitrogen reporting bases.
What it cannot support: A doctoral thesis with limited treatment replication does not provide chronic nitrate, chronic no-effect levels, transport limits or home targets.
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Controlled experiment
Direct Neocaridina evidence
Vazquez et al., 2017. Journal of Crustacean Biology 37(4): 367-373.
Source taxon as published: Neocaridina davidi
Study shape: Newly hatched shrimp were randomly assigned to 2.5, 5 or 10 animals/L for 90 days in 2 L vessels containing 5, 10 or 20 shrimp. The results table reports 8, 9 and 7 vessel replicates, respectively. A second experiment randomly assigned ten 30-day juveniles to each of five mixed-sex, five female-only and five male-only vessels at 5 animals/L.
Experimental unit: Two-litre vessel. Shrimp in each vessel were weighed together every 30 days in the density experiment, so the repeated response was vessel mean mass rather than an individually tracked trajectory. Whole-vessel biochemical homogenates were pooled across replicates when biomass was insufficient.
Environment: Two-litre culture vessels at 27 +/- 1 C with 0.7 g Java moss, continuous aeration and weekly complete water replacement
Endpoints: vessel mean wet mass through 90 days, model-estimated survival, phenotypic sex ratio, presence of ovigerous females, whole-vessel glycogen, lipid and protein concentration, mixed-sex versus monosex vessel mean mass and survival.
What it can support: Under the tested juvenile grow-out conditions, vessel mean mass diverged after day 30 and was lower at 10 animals/L than at 2.5 or 5 animals/L by days 60 and 90. Final females at 2.5 animals/L were 45 percent heavier than females at 10 animals/L, males at 2.5 animals/L were heavier than males at both higher densities, and model-estimated 90-day survival did not differ statistically among densities. Monosex versus mixed culture did not change mean mass or survival in the second experiment.
What it cannot support: This does not establish shrimp per gallon, a home-aquarium carrying capacity, a disease or welfare threshold, or a minimum starter group. The units were small juvenile grow-out vessels with daily food described as ad libitum and approximately 4 percent of vessel biomass, continuous aeration, weekly complete water replacement and removal of every new offspring. Individuals were not tracked, starting vessel counts were unequal across densities, brood and family contributions were not reported, food intake was not measured, and ovigerous presence was recorded without egg, hatch or recruitment outcomes. Survival percentages were model estimates rather than raw tank-wide guarantees. Biochemical samples sometimes pooled vessel replicates, weakening the original unit boundary. Ninety days does not represent a mixed-age, multigeneration colony or lifetime health.
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Controlled experiment
Direct Neocaridina evidence
Viau et al., 2016. Aquaculture Research 47(8): 2528-2542.
Source taxon as published: Neocaridina heteropoda heteropoda
Study shape: Water quality, biofilm processes, survival and growth were measured in a designed culture system.
Experimental unit: Culture vessel or substrate treatment unit
Environment: Aerated laboratory biofilm culture with zero routine water exchange
Endpoints: nitrogen compounds, dissolved oxygen, survival, growth.
What it can support: A deliberately designed and aerated biofilm system can contribute to water processing and juvenile culture.
What it cannot support: It does not validate an unaerated jar, every visible home biofilm, a no-water-change rule or a filterless aquarium.
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System observation or method study
Adjacent aquarium-system evidence
Bagchi et al., 2014. PLOS ONE 9(12): e113515.
Source taxon as published: Freshwater aquarium microbial communities, not a Neocaridina animal experiment
Study shape: Nitrogen balances and attached ammonia-oxidizer communities were measured across biofilter media and time.
Experimental unit: Aquarium and sampled biofilter medium
Environment: Three freshwater aquarium biofilters
Endpoints: nitrogen conversion, ammonia-oxidizer abundance, spatial and temporal stability.
What it can support: Attached aquarium biofilters can account for a large measured share of nitrification in the studied systems.
What it cannot support: It does not prove a filter model, media volume, cycle duration, turnover rate or Neocaridina toxicity boundary.
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Controlled experiment
Adjacent aquarium-system evidence
Wert et al., 2008. Water Research 42(1-2): 372-378.
Source taxon as published: Pilot drinking-water biofilters, not an aquarium animal experiment
Study shape: Backwash chlorination, filter depth and filtration rate were compared while residual ammonia and biodegradable organic matter were measured.
Experimental unit: Pilot filter
Environment: Three pilot sand-and-anthracite drinking-water filters
Endpoints: ammonia conversion, nitrite, nitrate, biodegradable organic matter removal.
What it can support: Backwash disinfection history and filtration rate changed nitrification in these pilot drinking-water filters.
What it cannot support: A municipal pilot filter does not prescribe aquarium rinsing, flow, media replacement or safe shrimp exposure, and chlorine effects depend on the tested system.
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