Tank & Tendril is a working ichthyologist's reference for the fish, invertebrates, and plants that live in ordinary home aquaria. Most of what's published here started as a tank-log entry, a water-test record, a quarantine observation, or a question a reader sent in. Every guide is written to answer that question well enough that you don't need to read three more.
The author
Dr. Helena Marlow, M.Sc., Ph.D.
I hold an M.Sc. in Aquatic Biology from the University of St Andrews and a Ph.D. in Freshwater Ichthyology from the University of Edinburgh, with field experience across the East African Rift, the Mekong Basin, and the Pantanal. From 2014 to 2018 I held a postdoctoral fellowship at the Smithsonian National Museum of Natural History's Division of Fishes, examining cichlid trophic specialisation in Lake Tanganyika. Since 2018 I have written full-time for general audiences while maintaining nine planted home aquaria — a soft-water Southeast Asian community, a hard-water rocky-shore Tanganyikan, two Amazon blackwater shrimp-only tanks, and a long-running South American biotope — that together provide a continuous record of more than thirty years of home-aquarium observation.
I am affiliated with the Senckenberg Research Institute's ichthyology section and a corresponding member of the IUCN Freshwater Fish Specialist Group.
What this site is for
Most online aquarium content is written by people who do not keep the fish. The result is a strange mixture of correct-sounding advice that does not survive contact with a real tank, a real water source, and a real fish population. The aim of Tank & Tendril is to be a place where the advice has been tried — on actual water, with actual fish, across a decade or more.
Each entry on this site is one of two things:
- A pillar guide — a long reference covering an entire family or topic area, written to be read once and consulted often.
- A species or topic guide — a focused profile of a single species, plant, or practical question, attached to its parent pillar.
The structure mirrors how I think about an aquarium: the family tells you what kind of fish you are looking at; the species tells you what its water, its tankmates, and its diet need to be.
Editorial principles
- Use scientific names. Common names vary by exporter and by decade; Latin binomials do not. Fish are referred to by binomial first, common name in parentheses on first mention. Where Fricke, Eschmeyer & Van der Laan (the Catalog of Fishes) has revised a name in the last decade, both the old and current names appear together.
- Cite the parameters. "Soft, acidic water" is meaningless. "TDS 60 ppm, GH 2 °dH, KH 0 °dH, pH 6.2, conductivity 110 µS/cm at 25 °C" is something you can measure and reproduce.
- Distinguish observation from inference. A behaviour observed across multiple tanks is reportable. A behaviour reported in a single online thread is not the same thing. Where the literature disagrees with what is visible in life, the article says so.
- Don't sell. Tank & Tendril does not run affiliate links to filter brands, light manufacturers, or fish retailers. If a particular product or supplier is mentioned by name, it is because their work is genuinely good.
- Update when wrong. If you find an error or a missed taxonomic update, write in via the contact page.
Editorial review
Articles are reviewed annually for taxonomic accuracy and to incorporate new ichthyological literature. The most recent full review was completed before the launch of the rebuilt site in May 2026. Each pillar carries the date of its last substantive revision in its frontmatter.
Reference works
The following sources are consulted regularly and cited where used:
- FishBase — taxonomy, distribution, and life-history database
- Catalog of Fishes — Fricke, Eschmeyer & Van der Laan, the authoritative species-name resource
- IUCN Red List — conservation status, particularly for wild-caught species
- The Cichlid Aquarium — Paul V. Loiselle
- Aquarium Atlas (Volumes 1–3) — Hans A. Baensch & Rüdiger Riehl
- Atlas of Freshwater Aquarium Fish — Glen S. Axelrod et al.
- Aquatic Plants — Their Identification and Culture — Karel Rataj & Thomas J. Horeman
Get in touch
I read everything that comes through the contact form. Questions about a particular species, errata, and review-copy enquiries are all welcome.