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Crowd thread digest

What the crowd said: mixing Corydoras species

📊 Thread digest 🐟 Fish 📅 April 2026
Original question

Corydoras are often kept in groups of six or more, but do they need to be the same species, or can you mix and match types?

Thread quality (estimated)

0 to 100. Qualitative, not a verdict on who was “right.”

Engagement 78

Lots of personal tank stories, a teachable moment on species versus color forms, and a few noisy asides.

Contention 68

Hard lines on “same species only” versus “mixed tanks look fine here,” plus spats over the six-plus rule and shop advice.

Agreement 72

Bigger groups of one line often behave more cohesively; enough individuals per type still matters in mixes.

How we scored it: Qualitative estimates (engagement, disagreement, overlap), not a formula on raw reply counts.

Answers rolled into four bands

Same species (conspecifics) for the strongest shoal
Natural schooling with their own kind; color variants of one species often still group; some split mixed setups into species-only tanks and saw more personality 37%
37%
Mixed species can work, especially with numbers per line
Pairs or trios of several types, or larger menus of types, reported schooling or mingling at times 32%
32%
Often cluster by type anyway
Bronze with bronze, sterbai with sterbai, or one odd fish drifting while others stick to their subgroup 21%
21%
Side debates
Whether six-plus is a sales line, albino ID across species, rescue singles, interbreeding worries corrected toward real taxonomy 10%
10%

Where people diverged

  • “Must be the same” vs “mix freely”: some treated different Corydoras as interchangeable; others stressed identification down to species.
  • Minimum group size: argued as welfare science versus shop upsell, with rescue culture mixed in.
  • What counts as “schooling”: tight same-species packs versus occasional mixed milling in the same frame.
  • Interbreeding: one worry about “not same kin” was unpacked into separate species, not mere color morphs of one fish.

Where people overlapped

  • More of one type often increases confidence and visible group behavior, including reports that doubling a single-species group felt dramatic.
  • When only one or two of a type remain, several saw them tag along with another species more than a full same-species shoal would.
  • Tank length and footprint came up as the limiter once someone wanted many species at once.
  • Peaceful mix with peaceful mix was assumed; the fight was about social structure, not aggression between lines.
Practical takeaway

Note: Common names and albinism span multiple species. This digest summarizes chat, not taxonomy. Verify Latin names and temperature needs before you buy.

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