Sea Filly the Sea-horse, comes to the school of fish, and Rainbow and his best friend Blue, welcome her in.

Rainbow is excited to meet his hero, renowned hockey star Wayne Grunion when he comes to town for a visit.

In the school band, Mrs Chips gives Rainbow Fish the conch shell, the hardest instrument in the band to play. Rainbow is then forced to practice, and he does so, gradually making for a better performance at the school concert.

Sir Sword needs to finish third grade, so he attends Rainbow's school, the School Of Fish.

Sir Sword lends Rainbow a book that he becomes hooked on and cannot stop reading.

Blue wins the clamball championship for his school, but only because no one sees him drop the ball anywhere.

Rainbow's mother, Aqua, invites his teacher, Mrs Chips, to dinner, and Rainbow Fish is worried that Mrs Chips herself will act just like a teacher.

After watching Rainbow and Blue play it in Shipwreck Park, Sea Filly becomes addicted to a 2000 computer game called "Clam Blaster" and hardly does anything else. However, when she brings the video game to the School Of Fish one day and plays it there during a difficult maths test with Mrs Chips, she soon discovers that the video game itself is "dumb, violent and intellectually worthless".

Rainbow tries to put Sea Filly in the Halloween spirit, but then has a haunting Halloween dream, and wakes up to find that Sea Filly has actually scared him in his sleep.

Chomper is given the lead role in the school play, but he mistakenly believes that voice acting is for wimps.

Rainbow Fish helps Sir Sword dressed up as Santa Sword on Christmas Eve.