Acuario vs. pecera
The Spanish words 'acuario' and 'pecera' both refer to containers where aquatic life is kept. However, there are significant differences between them in terms of their size, function, and the type of aquatic life they house.
Acuario
An 'acuario' is a larger structure that can sustain a variety of aquatic life. It's usually used for both personal and professional purposes such as botanical and zoological collections.
Hoy fui a visitar el acuario local.
(Today I went to visit the local aquarium.)
Mi acuario es grande y tiene varias especies de peces.
(My aquarium is large and has various species of fish.)
Pecera
'Pecera' is generally used to refer to smaller, home-based tanks specifically designed for keeping fish. It's often meant for ornamental fishes and is not usually equipped to handle a diverse range of aquatic creatures.
Compré una pecera nueva para mis pececitos.
(I bought a new fish tank for my little fish.)
La pecera de Juan solo tiene dos goldfish.
(Juan's fish tank only has two goldfish.)
Summary
'Acuario' and 'pecera' are terms used to describe containers for aquatic life. While both can be enjoyed for their aesthetics or educational value, an 'acuario' is more likely to represent a complex ecosystem with different species, while a 'pecera' is usually specific to fish-keeping in a smaller scale at home.