Slipper ciliate
Paramecium caudatum Ehrenberg, 1834
Paramecium caudatum is a freshwater-context ciliate, not a label for every infusorian culture. It is bacterivorous in documented experiments and may be a conditional live-food resource, while stock, food and receiving consumer determine the outcome. A 200–300 µm range is only an observation guide. Do not infer a global range, brackish tolerance, water quality, culture purity or a treatment need from one sighting.
Water type
Freshwater
Biological group
Oligohymenophorea
Record type
Species
Recognition confidence
Medium
Ecological functions
Grazer, Live food
Aquarium impact
Context-dependent
Culture and management
Dedicated starter culture
Typical size
200 µm – 300 µm
Visible to the naked eye
No value supported by reliable evidence
Useful starting magnification
No universal threshold supported by reliable evidence
Identity, habitat, and ecological role
Identity and taxonomic resolution: This card addresses Paramecium caudatum Ehrenberg, 1834, placed here under the catalog convention in Oligohymenophorea, Peniculida, Parameciidae and Paramecium. A slipper-like outline, ciliation and swimming can orient observation, but related Paramecium and other ciliates overlap in appearance. A supplier label or culture name does not establish a species or clone. Use scaled morphology, multiple living cells and suitable diagnostic evidence when identification changes a decision.
Morphology and dimensions: Exact-species literature reports a 170–300 µm size context. The stored 200–300 µm range remains a practical guide for locating and scaling cells, not an identification boundary or food-value guarantee. Clone, growth phase, food and preparation can change observed dimensions. Individual cells may be hard to recognize without microscopy, but no retrieved evidence supports a universal naked-eye binary or a fixed magnification threshold for the species.
Freshwater and distribution context: One exact-species source describes P. caudatum in still freshwater bodies of the northern hemisphere. Other exact-species laboratory studies report salt responses that vary with clone, infection status, acclimation and endpoint. Those sources differ in context rather than proving one habitat rule. The card therefore records freshwater context only: it does not claim a complete native range, generic brackish status, salt tolerance or a transfer instruction for a culture.
Role in the food web: Controlled microbial-food-web studies document P. caudatum as a bacterivorous intermediate consumer. It can therefore be described as a grazer and, conditionally, as a live-food resource. Neither label certifies an unknown culture, identifies its associates, predicts a particular consumer's response or makes it a permanent aquarium cleaner. Food availability, density, prey size, consumer and system determine whether the documented role is relevant in a given observation.
Observation, culture, and ecological relationships
Sampling and source context: Keep a documented stock separate from unknown infusoria. Record source, date, water, vessel, culture age and any stated strain before interpreting a sample. A suspension can contain bacteria, debris or other organisms besides P. caudatum. Do not transfer unverified culture water between systems merely because cells look active. A source name does not prove purity, health status or taxonomic identity, and one observed drop cannot establish what is absent elsewhere in the system.
Observation and identification: Examine several living cells with a recorded scale, sample history and preparation. Shape, motion, ciliation, oral region and contractile vacuoles can support a cautious Paramecium orientation, yet they may not resolve species or clone. Do not present 40× as a universal minimum: magnification records how material was seen, not what it is. If species-level identity materially affects research, culture or feeding, use diagnostic morphology or molecular evidence suited to that question.
Aquarium meaning: A ciliate observation can show that microbial resources are present in that sample, but it does not diagnose dirty water, biological maturity, filter performance or disease. The impact is context-dependent: abundance, bacterial food, oxygen, consumer and unknown associates change the meaning of a culture. Neither its presence nor its absence demonstrates that a system is safe, balanced or in need of correction. Read the observation with measured system trends and its documented sample context.
Culture boundary and maintenance: Treat starter culture as traceable material maintained for a stated purpose, not as any cloud of infusoria. Studies show that food resource, ammonium exposure, clone and microbial association affect population performance; they do not supply a universal density, temperature, feeding or salinity recipe. Retain provenance, but do not infer that a named stock is axenic or pathogen-free. Restarting with unknown material only replaces one undocumented condition with another.
Ecological relationships: P. caudatum links bacterial resources to higher consumers in documented experimental food webs. The grazer and live-food labels describe that conditional relationship, not a recommendation to mix organisms or promise suitable nutrition. Establish the intended consumer, food-web context and culture condition. A population increase may reflect changing resources without proving that it will clean water, support a particular larva or indicate a fault in the receiving aquarium.
Risks, prevention and limits: The reviewed evidence supports observation, provenance and containment limits, not therapy, medication, chemical control or a universal prevention regime. Holospora undulata is reported as a natural parasite in a clone-specific study, but that is neither a diagnosis nor a treatment indication for a culture, animal or person. Limit transfer of unknown culture water and keep source context when a decision has health consequences. Do not use ciliate abundance as a trigger for treatment.
Identification and observation data
- Record type
- Species
- This is a species-level entry for Paramecium caudatum Ehrenberg, 1834, not a generic name for every slipper-like ciliate or infusorian culture. The stored ranks follow the catalog convention: Oligohymenophorea, Peniculida, Parameciidae and Paramecium. Shape, ciliation and swimming can orient observation, but a supplier label, culture name or photograph does not establish the species or a clone. Use appropriate diagnostic evidence when identity changes a decision.
- Recognition confidence
- Medium
- Identification confidence is medium because several live cells, scale, motion and morphology can support a cautious Paramecium orientation, while those features may not resolve P. caudatum or a clone. Food, growth phase and preparation affect appearance. No retrieved evidence makes a fixed magnification a species threshold. Retain source and sample context, and use specialist morphology or molecular evidence when species-level identity materially affects research, culture or feeding.
- Biological group
- Oligohymenophorea
- Paramecium caudatum is a ciliate protist handled in the protists-and-infusoria group. That group describes a motile single-cell organism; it does not make all ciliates interchangeable or confirm an aquarium sample as this species. The current taxonomic placement follows Oligohymenophorea, Peniculida, Parameciidae and Paramecium. Keep free-living observations separate from any host-associated finding, because an observed ciliate is not automatically a disease diagnosis.
- Ecological functions
- Grazer, Live food
- Grazer and live-food are conditional roles. Exact-species studies document bacterivory and an intermediate-consumer role, so a documented stock may become prey in a suitable food web. Those labels do not prove that an unknown infusoria culture is P. caudatum, nutritionally suitable, clean or appropriate for one consumer. Food resource, density, prey size, consumer and system determine whether the documented relationship applies to a particular culture.
- Aquarium impact
- Context-dependent
- Impact is context-dependent. A P. caudatum observation or culture is not evidence of water quality, biological maturity, filter performance, disease, purity or a permanent cleaning service. Bacterial food, density, oxygen, consumer and unknown associates change its local meaning. One source describes freshwater still-water context in the northern hemisphere, while clone-specific salt experiments have different scope; neither source justifies a global range, generic brackish status or salinity instruction.
- Culture and management
- Dedicated starter culture
- Starter culture means traceable material maintained for a stated purpose. Food resource, ammonium exposure, clone and microbial association affect P. caudatum population performance, so a named stock is not automatically pure, pathogen-free or transferable to another system. The evidence supplies no universal culture recipe. Keep provenance, inspect for unexpected change and avoid replacing a failing culture with unknown infusoria or transferring unverified culture water between systems.
- Typical size
- 200 µm – 300 µm
- The stored 200–300 µm range is a working observation guide for Paramecium caudatum, not an identification boundary, consumer-suitability rule or culture-health test. Retrieved exact-species literature reports a broader 170–300 µm context. Clone, growth phase, food and preparation can affect dimensions. Measure several living cells with a calibrated scale and retain the sample context; size alone cannot resolve the species, clone or quality of a culture.
- Visible to the naked eye
- No value supported by reliable evidence
- No binary visibility value is stored. Individual cells may be difficult to recognize without microscopy, while a dense suspension can look cloudy or active without revealing which ciliate or contaminant is present. The retrieved exact-species sources do not define a reproducible naked-eye threshold. Naked-eye appearance therefore cannot identify P. caudatum, certify a culture as clean or useful, or establish the reason for a visible change in aquarium water.
- Useful starting magnification
- No universal threshold supported by reliable evidence
- No fixed magnification value is stored because the retrieved exact-species evidence does not make 40×, or any other setting, a universal threshold for observing or identifying P. caudatum. Magnification can document how material was examined, but it cannot by itself resolve a species, clone, culture quality or health meaning. Use a recorded scale, several living cells and sample context; apply specialist morphology or molecular evidence where exact identity matters.
Links to Aquarium SOS
Microworld ecological network
Links based on documented kinship, food webs, biofilms, and ecological functions.
