Understanding the Plural of ‘Aquarium’: Rules, Usage, and Common Pitfalls

by

The word aquarium is familiar to many as a glass tank filled with water, home to fish and aquatic plants. But have you ever wondered what the correct plural of ‘aquarium’ is? Should you say “three aquariums” or “three aquaria”? Surprisingly, both forms are correct—but their usage depends on context, formality, and tradition.

The confusion arises because aquarium is a Latin-based noun, and English allows two pluralization patterns for such words. Mastering the pluralization of Latin-derived nouns not only polishes your English but also enhances your writing in academic, scientific, and professional contexts.

This article is designed for students, English language learners, teachers, writers, editors, and anyone interested in advanced vocabulary or grammar. You’ll learn the definitions, pluralization rules, example sentences, common pitfalls, exercises, and advanced nuances of ‘aquarium’ and its plurals. By the end, you’ll confidently choose the right plural for any situation!

Table of Contents

  1. Definition Section
  2. Structural Breakdown
  3. Types or Categories
  4. Examples Section
  5. Usage Rules
  6. Common Mistakes
  7. Practice Exercises
  8. Advanced Topics
  9. FAQ Section
  10. Conclusion

Definition Section

3.1 What Is an ‘Aquarium’?

An aquarium is a transparent tank, bowl, or similar container in which fish, aquatic animals, and plants are kept. The term can also refer to a building or institution that houses collections of aquatic life for public viewing.

Etymology: The word aquarium comes from the Latin aquārium, which combines aqua (“water”) and the suffix -arium (“place of” or “container for”).

3.2 Grammatical Classification

  • Part of speech: Noun
  • Countable vs. uncountable: Aquarium is a countable noun. You can have one aquarium, two aquariums, etc.
  • Concrete noun: Aquarium is a concrete noun—it refers to a physical object you can see and touch.

Examples:

  • We bought a new aquarium for our goldfish.
  • The city’s aquarium is famous for its shark exhibit.

3.3 Function and Usage Contexts

The noun aquarium can function as the subject, object, or complement in a sentence.

  • Subject: The aquarium houses rare jellyfish.
  • Object: She cleaned the aquarium thoroughly.
  • Complement: Her dream was to own a large aquarium.

Common contexts include science classes, hobby discussions, public attractions, and educational settings.

3.4 Pluralization in English: A Brief Overview

In English, most nouns form their plural by simply adding -s or -es (e.g., cat → cats, box → boxes). These are called regular plurals.

However, many English words are borrowed from Latin or Greek. These loanwords sometimes retain their original foreign plural forms (e.g., criterion → criteria, datum → data). The word aquarium is one such example.

Structural Breakdown

4.1 The Two Plural Forms: ‘Aquariums’ vs. ‘Aquaria’

The word aquarium has two accepted plural forms in English:

  • Aquariums – the standard English plural
  • Aquaria – the classical Latin plural
Table 1: Comparison of ‘aquarium’, ‘aquariums’, and ‘aquaria’
Form Number Usage Frequency Register Example
aquarium Singular Common All This aquarium is beautiful.
aquariums Plural Most common General, Everyday We visited several aquariums.
aquaria Plural Less common Scientific, Formal The aquaria displayed diverse species.

4.2 Rule 1: Regular English Plural (‘Aquariums’)

  • Rule: Add -s to form the regular English plural: aquarium → aquariums.
  • This form is used in most everyday and informal contexts.
  • It follows the standard English rule for making countable nouns plural.

Examples:

  • There are five aquariums in the city.
  • Children love visiting aquariums.

4.3 Rule 2: Latin Plural (‘Aquaria’)

  • Rule: Change the -um ending to -a to form the Latin plural: aquarium → aquaria.
  • This form is preferred in scientific, academic, and formal writing.

Examples:

  • The laboratory maintains several aquaria for research.
  • Rare species are kept in specialized aquaria.

4.4 Pronunciation Differences

Both plural forms are pronounced differently. Here is a quick guide:

Table 2: Pronunciation Guide
Form IPA Pronunciation Syllable Stress Audio Symbol
aquarium /əˈkweəriəm/ kwe-AR-i-um uh-KWAIR-ee-um
aquariums /əˈkweəriəmz/ kwe-AR-i-ums uh-KWAIR-ee-umz
aquaria /əˈkweəriə/ kwe-AR-i-a uh-KWAIR-ee-uh

4.5 Spelling Considerations

  • The correct plural forms are aquariums and aquaria.
  • Common misspellings include aquarias, aquariea, and aquariuns.
  • Do not use aquariumses or aquarium’s as plurals.

4.6 Frequency and Register

Usage frequency and choice of plural depend on context and audience.

Table 3: Usage Frequency and Register
Plural Form Frequency (Google Ngram / COCA) Register/Context Example
aquariums Higher General, Everyday, Informal Many aquariums host daily shows.
aquaria Lower Scientific, Formal, Academic Studies in aquaria reveal fish behavior.

Types or Categories

5.1 Types of ‘Aquarium’ Plurals in English

  • Aquariums: The regular plural, widely accepted in modern English.
  • Aquaria: The classical/Latin plural, often used in scientific and academic fields.

5.2 Variations in Regional Usage

Preferences for plural forms can differ between English-speaking regions.

Table 4: Regional Preferences for ‘Aquariums’ and ‘Aquaria’
Region Preferred Plural Context
American English Aquariums (much more common) General, media, education
British English Aquariums (common), Aquaria (academic) Media, formal science writing
Australian English Aquariums All contexts
Canadian English Aquariums All contexts

5.3 Contextual Usage by Field

The choice of plural is often determined by the field or type of writing.

Table 5: Contextual Examples by Field
Field/Context Plural Used Example Sentence
Science (biology, zoology) Aquaria Researchers monitored the temperature in all aquaria.
Education (school textbooks) Aquariums Many schools have small aquariums in biology labs.
Journalism (news articles) Aquariums New aquariums are opening across the country.
Everyday conversation Aquariums Do you keep any aquariums at home?

Examples Section

6.1 Simple Sentences Using Each Plural Form

With “aquariums”:

  • There are several aquariums in this city.
  • My friends collect rare fish in their aquariums.
  • The children love visiting aquariums on weekends.
  • Most aquariums have special exhibits for kids.
  • The teacher cleaned all the aquariums after class.
  • Her aquariums are beautifully decorated.
  • Public aquariums attract many tourists.
  • Three aquariums in the region offer night tours.
  • I bought new filters for my aquariums.
  • Some aquariums specialize in saltwater species.

With “aquaria”:

  • Several aquaria display endangered fish species.
  • The scientist compared the water quality of the aquaria.
  • Museum aquaria house rare corals.
  • These aquaria are designed for research purposes.
  • All aquaria must be kept at a stable temperature.
  • The aquaria were cleaned and restocked last week.
  • In academic papers, the plural form “aquaria” is often used.
  • Some aquaria focus on freshwater ecosystems.
  • The laboratory maintains three aquaria for experiments.
  • Research on fish behavior was conducted in the aquaria.

6.2 Complex and Compound Sentences

  1. Although the aquariums were closed for renovation, the staff continued to care for the animals.
  2. Many aquariums, which are located near the ocean, feature local marine life.
  3. Some aquariums are privately owned, while others are funded by the government.
  4. The aquaria, which were built in the nineteenth century, still attract thousands of visitors.
  5. Researchers observed that fish in larger aquaria exhibited less stress.
  6. After visiting several aquariums, the students wrote reports on their favorite exhibits.
  7. The aquariums that house tropical fish must be kept warm at all times.
  8. Because the aquaria were newly constructed, the water chemistry had to be closely monitored.
  9. While some aquariums offer interactive experiences, others focus on conservation and research.
  10. The aquaria in the marine biology institute are equipped with advanced filtration systems.

6.3 Examples in Different Registers

Formal:

  • All aquaria should be regularly maintained to ensure optimal conditions for aquatic life.
  • The aquaria at the research center were meticulously designed for specialized studies.
  • Aquaria across Europe have reported a surge in visitor numbers.
  • Researchers use multiple aquaria to replicate diverse environments.
  • The aquaria’s filtration systems require weekly inspections.

Informal:

  • I love going to aquariums with my friends.
  • Do you keep any aquariums at home?
  • She has three aquariums in her living room.
  • We bought new fish for our aquariums yesterday.
  • Most aquariums have cool shark tanks.

Academic:

  • The experiment utilized six aquaria, each with different salinity levels.
  • Comparative studies in aquaria yield valuable ecological data.
  • The aquaria were calibrated according to standard protocols.
  • Previous research has documented similar trends in laboratory aquaria.
  • Results indicate that aquaria size influences fish growth rates.

6.4 Comparative Examples

Comparative Example Sentences
With “Aquariums” With “Aquaria”
We visited several aquariums during our trip. Researchers studied the behavior of fish in multiple aquaria.
Public aquariums are popular tourist attractions. All aquaria in the facility are cleaned weekly.
She enjoys maintaining her home aquariums. The university maintains three research aquaria.
Most aquariums have feeding demonstrations daily. The aquaria were monitored for changes in pH levels.
Children love colorful fish in aquariums. The study included data from both freshwater and marine aquaria.

6.5 Special Contexts

  • A pair of aquariums was donated to the school.
  • Several large aquaria are found in the oceanography department.
  • Many public aquariums host educational workshops.
  • A group of aquaria was relocated for renovation.
  • Both saltwater and freshwater aquariums are popular among hobbyists.
  • The number of aquaria in the region is increasing.
  • Some unique aquariums feature bioluminescent organisms.
  • All the laboratory’s aquaria are equipped with heaters.
  • Most city aquariums offer guided tours.
  • The collection of aquaria is impressive.

6.6 Tables of Examples

Table 6: Singular vs. Plural Forms in Context
Singular Plural (Aquariums) Plural (Aquaria)
This aquarium is clean. These aquariums are clean. These aquaria are clean.
The aquarium attracts many visitors. All aquariums attract many visitors. All aquaria attract many visitors.
My aquarium has goldfish. My aquariums have goldfish. My aquaria have goldfish.
Table 7: Error Correction – Wrong Plural to Correct Plural
Incorrect Correct Explanation
There are many aquarias in this museum. There are many aquaria in this museum. Latin plural is “aquaria,” not “aquarias.”
All the aquarium are beautiful. All the aquariums are beautiful. Regular plural adds “-s.”
The aquariums is large. The aquariums are large. Plural subject needs plural verb (“are”).
Table 8: Example Sentences by Register and Field
Register/Field Plural Used Example
Informal Conversation Aquariums I have three aquariums at home.
Formal Academic Aquaria The aquaria were observed for six months.
Journalistic Aquariums City aquariums report record attendance.
Scientific Aquaria Data from the aquaria supported the hypothesis.

6.7 Summary List

  • We visited three aquariums last summer.
  • The aquaria contained different species of fish.
  • Most aquariums are open to the public on weekends.
  • Researchers compared the water temperature in all aquaria.
  • Her aquariums need new filters.
  • The laboratory has two saltwater aquaria.
  • Children enjoy feeding fish in aquariums.
  • The aquaria were cleaned by the staff.
  • Public aquariums often host educational workshops.
  • All aquaria must be monitored for algae growth.

Usage Rules

7.1 General Rule for Pluralizing ‘Aquarium’

  • Use aquariums for general, informal, and everyday contexts.
  • Use aquaria for scientific, academic, or formal contexts.
  • Both are correct, but consistency in your writing is important.

7.2 Register and Audience Considerations

  • Aquariums: Suitable for general audiences, hobbyists, children, and non-specialist writing.
  • Aquaria: Preferred in scholarly articles, research papers, and formal publications.

7.3 Consistency of Usage

  • Choose one plural form and use it consistently within the same document or context.
  • Mixing “aquariums” and “aquaria” in the same text can confuse readers.

7.4 Agreement with Verbs and Pronouns

  • Plural forms take plural verbs and pronouns.
Table 9: Agreement Examples (Singular/Plural)
Subject Verb Example
aquarium (singular) is This aquarium is beautiful.
aquariums (plural) are These aquariums are beautiful.
aquaria (plural) are The aquaria are well-maintained.

7.5 Special Cases and Exceptions

  • With compound nouns: freshwater aquariums, saltwater aquaria
  • In foreign languages or multilingual contexts, use the plural appropriate for the language.

Other Latin-derived nouns ending in -um also have two plurals. Here are some examples:

Table 10: Comparison of Latin Pluralization Patterns
Singular English Plural Latin Plural Example
stadium stadiums stadia Two new stadiums/stadia were built.
datum datums data The data are conclusive.
medium mediums media Social media are influential.
memorandum memorandums memoranda Memoranda were distributed.

Common Mistakes

8.1 Overgeneralization of Regular Plurals

  • Using aquariums exclusively in formal or scientific contexts, where “aquaria” is often preferred.

8.2 Misapplication of Latin Plurals

  • Using aquaria in everyday conversation or casual writing, which can sound overly formal or pretentious.

8.3 Spelling Errors

  • Common mistakes: aquarias, aquariea, aquariuns, aquarium’s

8.4 Incorrect Subject-Verb Agreement

  • Using singular verbs with plural subjects: The aquariums is large. (should be are)
  • Using plural verbs with singular subjects: The aquarium are clean. (should be is)

8.5 Mixing Plural Forms within the Same Text

  • Switching between aquariums and aquaria inconsistently in the same paragraph or document.

8.6 Table of Common Mistakes

Table 11: Incorrect vs. Correct Plural Forms in Sentences
Incorrect Correct Rule
Many aquarias are found in Europe. Many aquaria are found in Europe. Latin plural: -um → -a
The aquariums is beautiful. The aquariums are beautiful. Plural subject, plural verb
She has three aquarium at home. She has three aquariums at home. Use plural for more than one
Some aquaria’s are large. Some aquaria are large. No apostrophe in plural

8.7 Quick Correction Guide

  • Mistake: “Many aquarias exist.”
    Correction: “Many aquaria exist.”
  • Mistake: “The aquariums is full.”
    Correction: “The aquariums are full.”
  • Mistake: “I bought two aquarium.”
    Correction: “I bought two aquariums.”
  • Mistake: “These aquariums and aquaria are different.”
    Correction: “These aquariums are different.” (stay consistent)
  • Mistake: “Some aquaria’s are empty.”
    Correction: “Some aquaria are empty.”

Practice Exercises

9.1 Fill-in-the-Blank Exercises

  1. There are five __________ in the city. (aquariums / aquaria)
  2. The research was conducted in several __________. (aquariums / aquaria)
  3. We visited two new __________ last weekend. (aquariums / aquaria)
  4. The scientists observed the fish in the __________. (aquariums / aquaria)
  5. All the __________ are cleaned daily. (aquariums / aquaria)
  6. Rare species are kept in special __________. (aquariums / aquaria)
  7. Do you keep any __________ at home? (aquariums / aquaria)
  8. The laboratory maintains three __________ for experiments. (aquariums / aquaria)
  9. School children often visit local __________. (aquariums / aquaria)
  10. Water temperature must be monitored in all __________. (aquariums / aquaria)

9.2 Error Correction

  1. She has two aquarium in her apartment.
  2. The aquariums is fascinating.
  3. Many aquarias are found in this region.
  4. The aquaria’s are cleaned weekly.
  5. Public aquarium host daily shows.
  6. I bought three new aquaria for my office.
  7. The aquariums was full of colorful fish.
  8. Some aquariums and aquaria is open on Sundays.
  9. He owns several aquarium.
  10. The aquariums are closed for renovation.

9.3 Identification Exercise

Identify if the plural usage is correct (C) or incorrect (I):

  1. The aquariums are large and well-maintained.
  2. Three aquaria was built for the experiment.
  3. I keep two aquariums at home.
  4. Many aquarias are open to the public.
  5. The aquaria are filled with tropical fish.
  6. Some aquariums is closed today.
  7. She visits different aquariums every summer.
  8. The aquaria’s water is tested weekly.
  9. Researchers used multiple aquaria for the study.
  10. There are several aquarium in the store.

9.4 Sentence Construction

Write five sentences using aquariums and five using aquaria.

  • Example with “aquariums”: I cleaned all my aquariums yesterday.
  • Example with “aquaria”: The aquaria require constant monitoring.

9.5 Table-Based Exercises

Table 12: Match the Singular to the Correct Plural
Singular Plural (Regular) Plural (Latin)
aquarium
stadium
datum
medium
memorandum

9.6 Advanced Application

Pluralize the following sentences using the correct Latin plural form:

  1. The datum is incorrect.
  2. This stadium is large.
  3. The memorandum is important.
  4. This medium is outdated.
  5. The bacterium is dangerous.

9.7 Answers and Explanations

  • 9.1 Fill-in-the-Blank Answers:
    1. aquariums
    2. aquaria
    3. aquariums
    4. aquaria
    5. aquariums
    6. aquaria
    7. aquariums
    8. aquaria
    9. aquariums
    10. aquaria
  • 9.2 Error Correction:
    1. She has two aquariums in her apartment.
    2. The aquariums are fascinating.
    3. Many aquaria are found in this region.
    4. The aquaria are cleaned weekly.
    5. Public aquariums host daily shows.
    6. I bought three new aquariums for my office. (unless academic context, then “aquaria” possible)
    7. The aquariums were full of colorful fish.
    8. Some aquariums and aquaria are open on Sundays.
    9. He owns several aquariums.
    10. The aquariums are closed for renovation. (Correct)
  • 9.3 Identification Exercise:
    1. C
    2. I (should be “were built”)
    3. C
    4. I (should be “aquaria”)
    5. C
    6. I (should be “are closed”)
    7. C
    8. I (should be “aquaria’s” only for possessive, not plural)
    9. C
    10. I (should be “aquariums”)
  • 9.5 Table-Based Exercises:
    Singular Plural (Regular) Plural (Latin)
    aquarium aquariums aquaria
    stadium stadiums stadia
    datum datums data
    medium mediums media
    memorandum memorandums memoranda
  • 9.6 Advanced Application:
    1. The data are incorrect.
    2. These stadia are large.
    3. The memoranda are important.
    4. These media are outdated.
    5. The bacteria are dangerous.

Advanced Topics

10.1 Historical Development of ‘Aquaria’ and ‘Aquariums’

The word aquarium entered English in the mid-19th century. Initially, only the Latin plural aquaria was used, especially in scientific writing. Over time, as English speakers applied standard pluralization, aquariums became common, especially in general contexts. Today, both forms coexist, reflecting the evolution of English usage.

10.2 Latin Pluralization in English: Broader Patterns

Many Latin nouns ending in -um have two plurals in English. Some are more common in their Latin form (e.g., data for datum), while others use the English plural.

Table 13: Common ‘-um’ Nouns and Their Plural Forms
Singular English Plural Latin Plural Preferred Usage
aquarium aquariums aquaria Both are correct
datum datums data data (scientific); datums (cartography)
medium mediums media media (mass communication); mediums (spiritualists)
memorandum memorandums memoranda Both; “memoranda” in formal/business
curriculum curriculums curricula curricula (academic)

10.3 Stylistic Choices and Editorial Guidelines

  • Chicago Manual of Style: Both “aquariums” and “aquaria” are acceptable; use “aquaria” in scientific contexts.
  • APA Style: Accepts both, but suggests consistency and appropriateness for audience.
  • MLA Style: Favors “aquaria” in academic writing.
  • General Rule: Check the style guide for your discipline or publisher.

Recent corpus studies (Google Ngram, COCA) show that “aquariums” is by far more common in general English, while “aquaria” appears more frequently in scientific literature.

Table 14: Usage Statistics (Google Ngram, COCA)
Year/Context Aquariums (per million) Aquaria (per million)
1980 (General) 0.7 0.05
2020 (General) 1.3 0.09
2010 (Scientific) 0.2 0.7

10.5 Influence of Register and Audience on Plural Choice

Use aquariums for general readers, websites, news, and casual writing. Use aquaria for scientists, scholars, and formal publications. Always maintain consistency!

10.6 Pluralization in Technical and Scientific Writing

Technical and scientific publications prefer aquaria for clarity and to align with Latin pluralization conventions. Museum guides and educational materials may use either, based on audience.

FAQ Section

  1. What are the correct plural forms of ‘aquarium’?

    The accepted plural forms are aquariums (regular English plural) and aquaria (Latin plural).
  2. Is ‘aquariums’ or ‘aquaria’ more correct?

    Both are correct. “Aquariums” is more common in general English, while “aquaria” is preferred in scientific and formal contexts.
  3. When should I use ‘aquariums’ vs. ‘aquaria’?

    Use “aquariums” in everyday, informal, and general writing. Use “aquaria” in academic, scientific, or formal texts.
  4. Are there differences between American and British English usage?

    Both forms are recognized in American and British English, but “aquariums” is more common overall. “Aquaria” is found more in academic contexts regardless of region.
  5. Can both plural forms be used interchangeably?

    Yes, but it’s best to stay consistent within a single text.
  6. Is ‘aquaria’ only used in scientific writing?

    No, but it is preferred in scientific and formal contexts.
  7. How do I know which plural to use in an academic paper?

    Check your discipline’s style guide. If in doubt, “aquaria” is usually safer for scientific or academic contexts.
  8. Are there other words in English with more than one plural form?

    Yes! Examples: stadium/stadia, datum/data, medium/media.
  9. Why does ‘aquarium’ have two plurals?

    Because it comes from Latin, which uses the -um/-a pluralization. English also allows the regular -s plural.
  10. How do I pronounce ‘aquaria’ and ‘aquariums’ correctly?

    See the pronunciation table above: “aquariums” (/əˈkweəriəmz/), “aquaria” (/əˈkweəriə/).
  11. What are some common mistakes with ‘aquarium’ plurals?

    Common errors include “aquarias” (should be “aquaria”), wrong verb agreement, and mixing both plural forms in one text.
  12. How can I remember the correct plural forms?

    Remember: -um nouns can take -s or change to -a. Use “aquariums” in general, “aquaria” in science.

Conclusion

The word aquarium has two accepted plural forms: aquariums and aquaria. Choosing the right form depends on your audience, context, and level of formality. “Aquariums” is widely used in everyday speech and writing, while “aquaria” lends a scholarly or scientific tone.

Understanding when and how to use each plural form is a valuable skill for students, writers, teachers, and professionals. Always strive for consistency in your usage, and consult style guides for formal writing. Mastering Latin plurals not only enhances your English but also deepens your appreciation for the richness of the language.

Continue exploring related grammar topics, such as Latin and Greek pluralization patterns, subject-verb agreement, and advanced vocabulary building. The more you practice, the more natural and confident your language use will become!

Leave a Comment