In species possessing more than a single dorsal fin, the space between the first and second fins.

A filter located inside the aquarium and typically used for smaller tanks due to its reduced capcity for media compared to external filters.

Set of fixed rules for the naming of animals and the resolution of problems in zoological nomenclature.

The world’s largest and most influential environmental organisation.

One of the bones comprising the operculum.

Of, relating to, or located on the interopercle.

Spine located on the interopercle, present in some fishes.

Of, relating to, or located on the space between the eyes

The shortest measurable distance between the eyes.

Located between two fin rays or spines.

The membrane connecting fin rays and spines in fishes.

Existing or occurring between different species. Opposite of intraspecific.

Relating to or inhabiting the small spaces between tissue, organs, or grains of a substrate.

Of or being the area between high and low tide marks; recurrently covered and exposed by tides.

Existing or occurring within a given species. Opposite of interspecific.

See exotic species.

Used in reference to a modified fin of a male which aids in transfer of gametes to the female during reproduction.

In zoological nomenclature, of an available name or nomenclatural act that is not valid under the ICZN code.

In zoological nomenclature, any available name for a taxon other than the valid name.

Most commonly used in reference to a native or non-native species with the tendency to spread widely that does or is likely to cause environmental, economic and/or ecological harm, though may also be applied to widespread, usually non-native, species that do not exert such adverse effects.