The HydroLibrary has a row of filter buttons at the top. Tap one to show only cards in that category. The six filters are: All, Authorities, Deterrents, Habitat, Invasive (INNS), and Endangered. Use the search box to find a specific species.

All

Everything — all 500+ species cards, plus all the authorities, deterrents, habitat projects, and water quality references. The default view.

Authorities

The 22 conservation authority profiles. Environment Agency, Natural England, the Wildlife Trusts, Rivers Trusts, IFCAs, and more. Useful when you're trying to figure out who to report a specific issue to.

Deterrents

The 5 deterrent method cards. Laser, audible scarers, visual deterrents, physical barriers, human disturbance. Useful reference when you're about to log a HydroDeter entry and want to check best practice for a specific method.

Habitat

The 22 habitat project cards. Active conservation and restoration projects you can learn about or contribute to.

Invasive (INNS)

Every invasive non-native species in the library. Signal crayfish, Himalayan balsam, harlequin ladybird, floating pennywort, zebra mussel, and so on. If you find an INNS, it's genuinely worth flagging — some are legally reportable.

Endangered

Species with critical, endangered, or Red List status. European eel, white-clawed crayfish, freshwater pearl mussel, vendace, water vole, dormouse, curlew, and similar. If you record one of these, the sighting has real weight — these are the species the conservation community most want data on.

The search box at the top of the library accepts common or scientific names. It searches as you type:

Filters and search combine. Set the filter to Endangered, then search "carp" — you'll see only Crucian Carp (which is Vulnerable) because the other carp aren't endangered.

Tapping a library card opens its detail page. From there: