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Interpret GH, KH, TDS, pH and conductivity: 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: What common water measurements represent, what they omit and which property a decision requires.

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Download this guide's 9 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
9
Direct Neocaridina
5
Direct controlled experiments
2
Supporting authorities
6
Named open questions
2
Public research changes
3

Registry reviewed 2026-08-12. Next scheduled review 2027-02-12. Read the editorial method.

Linked evidence records

Each record states what was measured and the nearest claim it cannot support. One source can serve several guides, so dossier totals must not be added together.

Controlled experiment Direct Neocaridina evidence

Molecular cloning and functional analysis of two calcium-associated cuticular protein genes in Neocaridina denticulata sinensis

Gao, Duan, Sun and Zhang, 2024. Journal of Oceanology and Limnology 42.
Source taxon as published: Neocaridina denticulata sinensis

Study shape: Two calcium-associated cuticle genes were cloned and profiled across molt stages and tissues. Small stage-matched groups received RNA interference, cuticle structure was examined by electron microscopy and recombinant proteins were tested for calcium and chitin binding.

Experimental unit: Individual shrimp, prepared tissue or isolated-protein assay, depending on endpoint; several RNA interference comparisons used three to five shrimp per group

Environment: Laboratory molt staging, molecular manipulation, microscopy and isolated-protein assays

Endpoints: molt-stage gene expression, cuticle ultrastructure, calcium binding, chitin binding, calcium carbonate precipitation.

What it can support: NdCAP-1 and NdCAP-2 expression varied by molt stage and tissue, gene knockdown changed cuticle surface structure and the recombinant proteins bound calcium and chitin under the tested assays.

What it cannot support: The study did not assign water calcium, magnesium, GH or diet treatments. Its small molecular-manipulation groups do not establish a hardness target, diagnose an incomplete molt or show that a mineral supplement prevents failure.

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System observation or method study Direct Neocaridina evidence

The lifecycle of Neocaridina denticulata and N. palmata in aquariums

Mahmoud, Sastranegara and Kusmintarsih, 2020. Biodiversitas 21(6): 2396-2402.
Source taxon as published: Market-sourced animals labelled Neocaridina denticulata and Neocaridina palmata; identification method not reported

Study shape: Thirty market-sourced animals per labelled species, 15 male and 15 female, first shared one aquarium per species. Fifteen ovigerous females per species were later described as moving to individual aquaria for egg and hatch observations, after which healthy offspring were reared and measured through a reported maturity sequence. Only descriptive statistics were stated.

Experimental unit: One initial aquarium per labelled species, so species and tank were confounded; the number, size and independence of the later female and offspring aquaria were not reported, and individual offspring tracking was not described

Environment: One 30-litre aquarium per labelled species with powerhead filtration, aeration, white stone, Java moss, twice-daily 40 percent protein pellets, partial water renewal every three weeks and naturally varying 25 to 28 C water

Endpoints: adult and post-hatching total length, egg length and width, attached egg count per female, reported time to life-stage labels, temperature, pH, dissolved oxygen, nitrate, ammonia.

What it can support: Under the reported culture history, the market-sourced groups produced attached eggs and direct-developing shrimp-like young. Fifteen females under each label supplied reported egg-count ranges of 21 to 60 for N. denticulata and 21 to 58 for N. palmata, and photographed post-hatching young measured about 3.3 mm at 24 hours.

What it cannot support: Species identity rested on market sourcing, colour and photographs without a diagnostic key or molecular confirmation. With one initial aquarium per label, species and tank were confounded, preventing an independent species comparison. Female isolation, offspring allocation, starting hatch denominators, survival, losses and repeated-animal tracking were not reported. The stated June 14 to August 10 breeding interval does not reconcile with 75-day and 80-day observations. Tables place ranges in columns labelled Means while also giving separate standard deviations, figures and axes are inconsistently numbered or labelled, and no inferential model is reported. Temperature and pH varied within the same systems rather than being assigned, so plots cannot establish 27 C as an optimum or any pH effect. The water methods, analyte bases and nitrogen interpretation are incomplete, and nitrite named in the abstract is not reported in the tables. Calling the direct-developing young larvae and describing a planktonic phase conflict with the better-resolved N. davidi developmental literature. The source cannot establish a universal 15-day incubation, 75-day maturity calendar, water-quality threshold, species difference or cultivation optimum.

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Field observation Neocaridina identity evidence

Life-history traits and ecological characteristics of the ornamental shrimp Neocaridina denticulata, recently introduced into the freshwater systems of Israel

Levitt-Barmats et al., 2019. Aquatic Invasions 14(4): 684-702.
Source taxon as published: Neocaridina denticulata, with identity uncertainty discussed by the authors

Study shape: Field occurrence, morphology and mitochondrial markers were combined with an unreplicated laboratory lineage; 18 third-generation larvae were separated for individual molt and growth observations.

Experimental unit: Field specimen or sampling site for field endpoints; individual jar for 18 third-generation growth observations

Environment: Thirty Israeli field locations plus laboratory observation at 20 to 25 C across three generations

Endpoints: field occurrence, morphology, COI and 16S sequences, embryo count, age at first ovigerous stage, molt interval, growth.

What it can support: The study documents a wide field-occurrence range and follows known-hatch third-generation individuals for molt and growth observations over 49 weeks under one laboratory protocol.

What it cannot support: Taxonomic placement within the complex remained uncertain, field occurrence is not a water optimum, and losses plus an incomplete growth series do not provide a replicated hatch-to-death lifespan distribution.

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Morphology or taxonomy Direct Neocaridina evidence

Neocaridina fonticulata, a new land-locked freshwater shrimp from Hengchun Peninsula, Taiwan (Decapoda, Caridea, Atyidae)

Shih, Cai and Chiu, 2019. ZooKeys 817: 11-23.
Source taxon as published: Neocaridina fonticulata Shih, Cai and Chiu, 2019, described from type and additional material collected at Sheding, Kenting, southern Taiwan

Study shape: The authors described a holotype, multiple paratype lots and additional field material using external morphology and drawings, compared material of Neocaridina ikiensis, measured five eggs from each of four ovigerous females, and analyzed a 658-base-pair mitochondrial COI segment from four Sheding specimens with Bayesian and maximum-likelihood phylogenetic methods and pairwise distances.

Experimental unit: Individual deposited specimen for morphology, four source shrimp for COI that yielded one reported haplotype, and 20 eggs nested within four ovigerous females for egg measurements

Environment: A leaf-litter layer in a small, slow-flowing headwater stream beside a spring outlet on a limestone hill at Sheding, Kenting; the paper reports about 25 C water, pH 7.06 to 7.16 and dissolved oxygen 7.33 to 7.70 mg/L at the collection site, while examined specimens were preserved in 70 to 95 percent ethanol

Endpoints: type locality and deposited material, rostrum and appendage diagnostic characters, male first and second pleopod morphology, egg dimensions, live colour description, COI haplotype and phylogenetic placement, pairwise mitochondrial distance.

What it can support: The combined type material, comparative morphology and sampled COI evidence support recognizing N. fonticulata as a distinct Neocaridina species in the reviewed 2019 treatment. Diagnostic evidence includes the rostrum, pereiopods and male first and second pleopods. The four sequenced shrimp produced one 658-base-pair COI haplotype, LC427866, and the smallest reported K2P distances to sampled N. ketagalan and N. saccam were 5.42 and 5.43 percent.

What it cannot support: The species was then known only from one Sheding locality, so the report does not establish its complete distribution, population size, seasonal habitat range or conservation status; the authors prediction that it may occur in eastern Taiwan was not a sampled result. Several diagnostic characters require an adult male, dissection and specialist comparison, so body colour or one aquarium photograph cannot identify the species or distinguish it from a trade morph. The molecular result used four shrimp, one mitochondrial haplotype and no nuclear locus, cross, genomic ancestry test or blind identification validation. Mitochondrial separation in this sample does not authenticate a seller label, certify a colour line, prove reproductive isolation or identify another animal by appearance. Site temperature, pH and dissolved oxygen are locality observations without temporal replication or an assigned comparison, not aquarium optima, tolerances or care targets. Aquarium-held photographs were for observation after collection, not a husbandry experiment.

Related source material: GenBank COI accession LC427866

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Controlled experiment Adjacent aquarium-system evidence

Assessing the Reliability of Water-Test Kits for Use in Pond Aquaculture

Naigaga et al., 2017. Journal of the World Aquaculture Society 48(4): 555-562.
Source taxon as published: Pond-aquaculture water samples and analytical methods, not shrimp

Study shape: Several field kits and strips were compared with standard methods by the management decisions each result would produce.

Experimental unit: Water sample and paired analytical-method comparison

Environment: Pond-aquaculture water analysis compared with standard methods

Endpoints: decision agreement, weighted kappa, analyte-specific disagreement.

What it can support: Reliability differed by kit and analyte, including nitrate decision disagreement for two tested strip products.

What it cannot support: The study does not validate every current product, make all strips inadequate or show that a kit result equals a laboratory concentration without method context.

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Controlled experiment Direct Neocaridina evidence

Assessment of a biofilm-based culture system within zero water exchange on water quality and shrimp survival and growth

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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Review or synthesis Broader ornamental-shrimp review

Neocaridina denticulata: A Decapod Crustacean Model for Functional Genomics

Mykles and Hui, 2015. Integrative and Comparative Biology 55(5): 891-897.
Source taxon as published: Policy review comparing Neocaridina denticulata with the crayfish Procambarus clarkii and Cherax quadricarinatus, with additional inferences from other crustacean models

Study shape: The authors defined desired traits for a decapod model, compared three freshwater candidates, summarized selected Neocaridina life-history, culture, anatomy and genomic claims from earlier publications, recommended N. denticulata, and proposed obtaining a complete genome and developing tissue-specific gene-control and mutant-screening methods.

Experimental unit: Published source or narrative claim; the paper reported no new animals, aquaria, assigned treatments, measurements or statistical analysis and did not describe a systematic search, eligibility criteria or risk-of-bias assessment.

Environment: No new animal experiment or culture trial; narrative synthesis and recommendation arising from a 2015 comparative Pancrustacea symposium workshop

Endpoints: model-organism selection criteria, comparative recommendation, summary of cited life-history and culture claims, summary of draft-genome status, proposed functional-genomics next steps.

What it can support: The paper documents that two authors recommended N. denticulata as a decapod functional-genomics model in 2015 based on its small space requirement, commercial availability, transparent cuticle, cited life-history traits and then-available preliminary genome. It explicitly identified a complete genome and reliable gene-expression manipulation as future work.

What it cannot support: This policy review is not a new replication of any cited experiment and is not a systematic review. Its pH 6.5 to 8.0, temperature up to 30 C, preferred 22 to 25 C and pH 7.0 to 7.5, 15 to 16 day intermolt, 20 to 30 egg, approximately 30 day hatch and 4 to 6 month maturity statements combine older sources, populations and methods; they are not one standardized aquarium comparison or validated species-wide optimum. The broad statement that N. denticulata is resistant to bacterial infection does not establish general disease resistance, a pathogen-free line, treatment or immune supplement. The cited DPrP bacterial-challenge paper remains full-text-needed in this registry, and the companion crayfish-plague citation studied a related published species against one oomycete pathogen. The preliminary genome was explicitly incomplete, and proposed transgenesis, reporter expression, mutation screening and targeted gene control were future possibilities rather than demonstrated Neocaridina methods in this paper. The review does not validate a care range, breeding calendar, stocking rule, disease guarantee, commercial-line assay or consumer genetic intervention.

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Morphology or taxonomy Direct Neocaridina evidence

Neocaridina iriomotensis, a new species of land-locked freshwater shrimp (Crustacea: Decapoda: Atyidae) from Iriomote Island, southern Ryukyus, Japan

Naruse, Shokita and Cai, 2006. Proceedings of the Biological Society of Washington 119(1): 25-31.
Source taxon as published: Neocaridina iriomotensis Naruse, Shokita and Cai, 2006, described from the upper reaches of Nishifunatsuki in the Nakama River, Iriomote Island, Japan

Study shape: The listed material contains one male holotype, 41 paratypes and 49 non-type specimens collected on seven dates from November 1999 through June 2000. Only specimens above 4 mm carapace length were used for the description. Characters were drawn with a camera lucida and measured to 0.01 mm; proportional summaries report medians, ranges and varying sample sizes from 73 to 83. The treatment compared the new species with published N. anhuiensis and topotypic N. ishigakiensis morphology.

Experimental unit: Individual field specimen for morphological ratios and qualitative seasonal comparison; the paper does not report the female or egg denominator underlying its egg-size and 21-to-82 clutch ranges

Environment: Field-collected from the lower part of a headwater reach in the upper Nakama River, described as about 5 to 10 m wide, approximately 1 m deep and slow-flowing, where shrimp occurred on aquatic vegetation and tree roots with Macrobrachium shokitai; no water chemistry or temperature was reported

Endpoints: deposited type and non-type material, rostrum armature and length, pterygostomian spine, pereiopod proportions, season-associated third-pereiopod form, male first and second pleopod morphology, egg dimensions and reported clutch range, habitat and distribution description.

What it can support: The 2006 morphological treatment supports recognizing N. iriomotensis within its stated species concept and distinguishes its sampled material from N. anhuiensis and N. ishigakiensis using combinations of rostrum, pterygostomian-spine, pereiopod and male pleopod characters. It also documents that the third pereiopod showed sex-associated form in summer specimens but no sexual difference in winter specimens, demonstrating that season can affect the availability of an identification character.

What it cannot support: All listed material came from one named upper-reach locality in the Nakama River, and qualitative wording that the shrimp was common lacks sampling effort and a population denominator. No molecular analysis was included; proposed headwater ecomorph populations had intermediate rostrum lengths and were retained only tentatively pending molecular and ecological study. Published comparisons relied partly on earlier descriptions rather than a balanced multi-population validation, character sample sizes varied because not every specimen contributed every ratio, and no blind key-performance test was conducted. Egg and clutch ranges lack female, clutch and egg denominators. The paper reports no water temperature, pH, hardness, conductivity, dissolved oxygen, nitrogen measurements, diet, culture comparison or aquarium outcome. It cannot identify an aquarium animal from colour or one photograph, authenticate a seller line, prove genetic separation or reproductive isolation, map the complete species range, establish population abundance, or supply a care target, breeding forecast or seasonal aquarium rule.

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Review or synthesis Adjacent biological evidence

Calcium balance and moulting in the Crustacea

Greenaway, 1985. Biological Reviews 60(3): 425-454.
Source taxon as published: Broad marine, freshwater and terrestrial Crustacea review

Study shape: Published work on calcium storage, loss, uptake and exoskeleton calcification was synthesized across crustacean taxa.

Experimental unit: Published source, not a new Neocaridina experiment

Environment: Review of crustacean calcium balance across environments and molt stages

Endpoints: calcium storage, environmental calcium uptake, hemolymph calcium, exoskeleton calcification.

What it can support: Calcium handling and calcification change across the crustacean molt cycle, and freshwater taxa have evolved calcium-uptake strategies.

What it cannot support: A broad crustacean review does not establish a Neocaridina GH optimum, diagnose a failed molt or show that adding a calcium product corrects an observed problem.

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Supporting authorities

These can govern a method, professional boundary, regulation, maintained identity record or manufacturer instruction. They are not counted as animal evidence.

Source and roleSupportsLimit
Specific Conductance
U.S. Geological Survey; Analytical method or chemistry authority
Professional measurement, calibration and reporting context for specific conductance.It does not turn conductivity or a converted TDS value into ionic composition or a shrimp-health verdict.
Open the authoritative source.
Measurement of pH
U.S. Geological Survey; Analytical method or chemistry authority
Professional pH calibration, sampling and reporting context.It does not validate every aquarium meter, reconstruct an old sample or define a species optimum.
Open the authoritative source.
A Primer on Water Quality
U.S. Geological Survey; Analytical method or chemistry authority
General water-quality context, including evaporation and dissolved-material concentration.It does not prescribe an aquarium top-off schedule, water-change percentage or shrimp parameter range.
Open the authoritative source.
Conductivity meter manual
National Institute of Standards and Technology; Analytical method or chemistry authority
Conductivity measurement, temperature compensation and TDS-conversion-factor context for the named instrument.A conversion factor does not reveal dissolved composition, hardness or a Neocaridina optimum.
Open the authoritative source.
Alkalinity and Water
U.S. Geological Survey; Analytical method or chemistry authority
General acid-neutralizing-capacity and buffering context.Alkalinity is not a direct pH control, carbonate inventory or species optimum without method and water context.
Open the authoritative source.
Hardness of Water
U.S. Geological Survey; Analytical method or chemistry authority
The definition and conventional reporting of calcium-and-magnesium water hardness.Hardness does not reveal every ion, diagnose a molt or establish a Neocaridina optimum.
Open the authoritative source.

Named open questions and searches

Reproducible search reviews

Public research changes affecting this guide

Source added2026-08-12

Another Neocaridina species is not a colour morph

Changed: The evidence registry and species guide now include the complete description of Neocaridina fonticulata, with its deposited material, diagnostic anatomy, sampled COI evidence and type-locality context kept separate from aquarium trade labels.

Why: The paper diagnoses a distinct species with rostrum, pereiopod and male pleopod characters plus one mitochondrial haplotype from four shrimp. Several characters require an adult male and specialist examination. One locality, one COI haplotype and live-colour photographs cannot identify a seller line, prove reproductive isolation, map a complete range or turn collection-site water values into care targets.

Knowledge gap refined2026-08-12

An extension species profile is not a parameter sheet

Changed: The species guide and supporting-authority registry now include the current UF/IFAS cherry-shrimp profile while explicitly separating its public labels and species overview from aquarium parameter advice.

Why: The official three-page PDF contains no recommended temperature, pH, GH, KH, conductivity, TDS, nitrogen, stocking, tank-size, water-change or feeding values. Its morph-name list has no crossing or genetic evidence, and most printed size, incubation, maturity, molting and cleanup statements do not expose the underlying denominators or conditions. The profile is useful professional orientation, but it cannot support the water-parameter requirements attributed to it by secondary hobby pages.

Claim scope narrowed2026-08-11

A model-organism recommendation is not a care standard

Changed: The genetics and husbandry boundary now includes the influential 2015 recommendation to develop Neocaridina as a functional-genomics model while identifying its care numbers and disease-resistance language as secondary synthesis, not new experimental evidence.

Why: The seven-page policy paper arose from a symposium workshop, compared three candidate species and reported no new animals or systematic review method. It explicitly listed a complete genome and reliable gene-control methods as future work, while its pH, temperature, maturity, molt and egg statements came from selected older sources.

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