Here is the full list of all 15 Chillquarium achievements.
Discover every fish from Freshwater Friends
Discover every painted fish from Freshwater Friends
Discover every golden fish from Freshwater Friends
Discover every fish from Rivers and Ponds
Discover every painted fish from Rivers and Ponds
Discover every golden fish from Rivers and Ponds
Discover every fish from Reef Fellas
Discover every painted fish from Reef Fellas
Discover every golden fish from Reef Fellas
Discover every fish from Marine Dwellers
Discover every painted fish from Marine Dwellers
Discover every golden fish from Marine Dwellers
Discover every fish from Giants
Discover every painted fish from Giants
Discover every golden fish from Giants