Garrett Hardin's 'Tragedy of the Commons' (1968) in fisheries economics describes open-access marine resources where individual fishers, acting rationally in self-interest to maximize their short-term catch, collectively deplete and overexploit the finite shared fish stock, causing commercial stock collapse.

Origin and invasive ecology of armored catfish (Pterygoplichthys spp.):

• The suckermouth armored catfish or 'pleco' (family Loricariidae, notably Pterygoplichthys pardalis and P. disjunctivus) is native to the tropical freshwater river basins of South America (Amazon, Orinoco, and Paraná basins). Introduced globally via the ornamental aquarium trade, it has escaped and established highly destructive invasive wild populations across Indian wetlands and rivers.
• North America has no native loricariid catfishes.
• China is native to carps and Asian catfishes.
• Africa is native to synodontid and clariid catfishes.

Ecological species categories:

• Keystone species play a disproportionately critical role in maintaining the structure and biodiversity of an ecological community (e.g., sea otters, top predatory sharks).
• Invasive species are non-native (alien) organisms introduced into an ecosystem that proliferate rapidly, outcompete native taxa for food and habitat, introduce novel diseases, and directly cause species extinctions, posing a severe threat to global biodiversity (e.g., African catfish Clarias gariepinus, suckermouth sailfin catfish, water hyacinth).
• Flagship species are charismatic species chosen to raise conservation awareness (e.g., giant panda, river dolphin).
• Indicator species reflect the environmental health of an ecosystem by their presence, absence, or abundance.