Photograph the right details
Capture a clear side view with the whole fish visible, preferably with fins extended naturally. Photograph both sides and more than one calm moment. Keep the original image without dramatic color adjustments. A close-up of the face can help, but should accompany a full-body view. Do not repeatedly chase or handle a fish just to obtain a diagnostic photograph.
Write down what you know
Record the exact shop name, scientific label, commercial form, source and any locality claim. Keep “sold as” separate from “confirmed as.” Note approximate size, sex if known and whether the fish is juvenile. A photograph of an adult male from the internet may be a poor comparison for a small female or a fish showing stress coloration.
Compare several traits
Look at body depth, tail shape, dorsal extensions, lateral bands, cheek markings and the position of dark spots. Color is useful context but can be changed by mood, lighting and selective breeding. The species profiles highlight practical distinctions; they are not a replacement for a formal diagnosis or an expert examining a difficult specimen.
Common trade traps
Orange Flash and Double Red are strain labels, not species. Pandurini is frequently used for panduro. Inka and A188 point toward baenschi in the trade. Fish sold as viejita deserve particularly careful scrutiny against macmasteri and related ornamental lines. A number or a confident seller’s label helps retrieve information, but does not itself verify the fish.
When to leave the answer open
If the available evidence is insufficient, use a provisional label and seek a specialist opinion with your photographs and source history. Do not breed uncertain related fish together and then distribute offspring under a precise species or locality name. “Identification unresolved” is more useful than a guess that becomes permanent in someone else’s records.
Further reading
Read species-specific sources alongside the profiles. This guide provides practical planning advice, not a universal recipe for every population.