Identifying Mystery Fish: Clear with Silver Head Markings

Caught small, translucent fish with silver head markings and upturned mouths in an apartment complex pond. Fed generic pond food. What are they?

Likely Candidates (Pennsylvania)

• Brook Silverside (Labidesthes sicculus): Transparent, silver lateral band, upturned mouth, surface dweller. Common in calm waters.
• Inland Silverside (Menidia beryllina): Similar, often introduced for mosquito control.
• Mosquitofish (Gambusia affinis): Females larger, gravid spot; males have gonopodium. Less transparent.
• Young Shad/Herring: Possible if connected to river (Allegheny 5 mi away).

Next Steps

1. Photograph clearly (side view, dorsal, anal fin).
2. Count dorsal/anal fin rays, note lateral line.
3. Post on iNaturalist or local fish ID group with location.

Feeding

Generic pond flakes/pellets are fine—these are omnivores. Offer crushed flakes, frozen daphnia, or live mosquito larvae.

Do not release into other waters. If non-native, humanely euthanize (clove oil overdose).