European Chub (Squalius or Leuciscus cephalus) shoal in the clear water of Plitvice Lakes National Park, Croatia. MORE INFO: Chub traditionally inhabit more lowland waters in Croatia, but they have proliferated since being introduced to Plitvice Lakes, which are warmer than in the past due to climate change, and they have reduced native trout populations considerably by predating their eggs.

School of chubs (Kyphosus sp.), Ilha do Meio, Fernando de Noronha national marine sanctuary, Pernambuco, Brazil, South America

Chubs (Kyphosus sectatrix) schooling, Fernando de Noronha, Pernambuco, Brazil, South America

School of chubs (Kyphosus sp.), Ilha do meio, Fernando de Noronha national marine sanctuary, Pernambuco, Brazil, South America