THE ANIMAL FILES

Guppy

Poecilia reticulata

Colour can attract a mate and catch a predator’s eye.

Wild male guppies are often much more colourful than females. Bright colours can attract mates but also predators; the fish may school or cautiously approach a predator to gather information.[1]

Follow the evidence ↓
Guppy
Image: Marrabbio2 · Commons · CC BY-SA 3.0
Wild appearance
Males are usually more brightly patterned[1]
Group behaviour
Schooling can help with predator avoidance[1]
Domestic forms
Selective breeding creates varied fins and colours[1]

Wild colour and selective breeding

Wild-type females tend to be greyer, while males carry varied coloured patches, stripes or spots. Selective breeding has produced domestic forms with very different fin shapes and ornamentation.[1]

Brightness has more than one audience

Brighter males can be attractive to females but also more conspicuous to predators. Patterns differ under different predation pressures, so colour is not simply a competition to become ever brighter. The same visible signal can carry a reproductive benefit and an ecological cost at the same time.[1]

Inspecting danger is still a risk

Some guppies approach potential predators to gather information, often avoiding the mouth region and approaching from the side or rear. They can inspect in groups.[1]

A COMMON MIX-UP

Is the brightest colour always the best outcome?

No. A colour pattern can help with mate attraction while increasing visibility to predators. The balance depends on local conditions, which is why wild populations need not all resemble the most ornamented domestic strain.[1]

TRY A LITTLE REASONING

Why might a fish approach something that could eat it?

Reveal the explanation

Predator inspection can provide information about a possible threat. That benefit does not remove the cost of proximity, so cautious approach direction and grouping are important parts of interpreting the observation.[1]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — Guppy (fixed revision; adapted and translated)
  2. NCBI Taxonomy — Poecilia reticulata (identity and classification)

Last fact check:

One discovery leads to another

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