The best way to reach me is by email. I read everything that comes in, but I cannot promise an individual reply to every message — I do answer questions that are likely to be useful to other readers by adding them to the relevant species or topic page.
What I am happy to hear about
- A species you cannot identify. Send a clear photograph (side profile, scale reference if possible), the source (local fish store, online retailer, wild-caught), and your water parameters at the time of acquisition. Mystery imports — the trade still ships unidentified or misidentified fish regularly — are a useful corrective and I usually find time to reply.
- A water-chemistry result that doesn't make sense. A consistent reading that contradicts what you would expect from your source water or your treatment regime is almost always informative. Send the readings, your test kit make, and the tank's history.
- A correction. If a guide on this site contains a factual error, a stale taxonomic name (the Catalog of Fishes updates frequently), or an inference that no longer holds against current literature, please tell me. Corrections are credited at the foot of the relevant page.
- A guide you would like to see. Suggestions for species or topics not yet covered are welcome and frequently shape what I write next.
- A press, interview, or speaking enquiry. Please mention the outlet, deadline, and the angle you are exploring.
What I cannot help with
- Rehoming unwanted fish. Please contact your local aquarium society, a reputable fish-only retailer that accepts returns, or a public-aquarium liaison — most regional zoos and aquariums maintain quarantine systems and will sometimes accept appropriate surrenders. I cannot accept fish.
- Diagnosing a sick fish from a single blurry photograph. Disease diagnosis requires water parameters, recent history, behavioural observation across multiple days, and ideally clear images of the lesion or behaviour. Bring all of that, and the answer is usually more useful.
- Pond, lake, or commercial-aquaculture consulting. This site is a home-aquarium reference. Production-scale and outdoor work are different disciplines and a different range of pathogens applies.
For all of the above, write to: helena.marlow [at] tankandtendril [dot] com
I aim to read messages within seven days. Responses are typically slower during the spring import window (March–May in the northern temperate zone), when new arrivals require quarantine attention.