Neon Tetra
Its bright colouring makes the fish visible to conspecifics(find each other/belongs to the same species) in the dark blackwater streams


Electric Eel
It is capable of generating powerful electric shocks, which it uses for both hunting and self-defense.

Angelfish
Pterophyllum(Angelfish) are unusually shaped for cichlids being greatly laterally compressed, with round bodies and elongated triangular dorsal and anal fins. This body shape allows them to hide among roots and plants, often on a vertical surface. Naturally occurring angelfish are frequently striped longitudinally, colouration which provides additional camouflage. Angelfish are ambush predators and prey on small fish
Andante / Adagio (Sea Horse and Zebrafish)






Seahorse
These fish form territories, with males staying in about one square meter of their habitat while females range about one hundred times that area. They bob around in sea grass meadows, mangrove stands, and coral reefs where they are camouflaged by murky brown and grey patterns that blend into the sea grass backgrounds. During social moments or in unusual surroundings, seahorses turn bright colors.




Zebrafish
It commonly inhabits streams, canals, ditches, ponds, and slow-moving to stagnant water bodies, including rice fields


Finale: Allegro giocoso (Guppy & Co.)




Guppy
Occasionally male guppies may behave aggressively towards each other, engaging in fin-nipping and other bullying behaviour. Guppies live in complex social networks, choosing social partners and remembering them.

Adapted from wikipedia.org