Though the Big Six (or Seven) are the main focus of the show, it's the minor characters that fill it out and make it great.
- Bubblychu is friends with Berryboo, but it's a troubled friendship. He is responsible for a number of the negative events in Squiddles (albeit normally inadvertently).
- Smiddlet (pink/fuschia) was a significant villain in a few seasons. He was a mutant, possessing wings, legs, etc. He was originally a normal Squiddle but was transformed by evil forces. After the Squiddles rejected him, he grew enraged. His most significant act was kidnapping Princess Berryboo, thus causing the ocean to become dirty and polluted (without her protection).
- Kelpberry appeared in only two seasons, but was popular during zir run (zey appear to have changed gender somewhere between the two seasons).
- Searoil (pale red) and Midgegirth (watery blue) are brothers. Searoil is one of the darker characters in the series - he is one of the only Squiddles to not have a naturally sunny disposition, and therefore has few friends. He has had a few plot important moments, as he is the only Squiddle good at making hard decisions. He frequently appears with conch and magicstar imagery; it is unclear whether this is going to be signiicant in later seasons. Midgegirth, his older brother, constantly tries to draw him out and get him to play with the other Squiddles.
- Merrymallow (off-white) appeared in three episodes only, but is remembered for her relationship with Lemony.
- Bubble Blast (bright blue) appeared in 4x17 and 4x18. An encounter with Skipper Plumbthroat caused her to lose a tentacle.
- Terri Able (Sea Unicorn) appeared in season 2 and 3 as a minor villain. Terri, being possesed by the power of hate and anger, his appearance was a very dark grey, red, and black. After Princess Berryboo saved Terri Able with her offering of friendship his appearnace changed back to a bright yellow and a few white stripes.
- Manta Ray Princess is the daughter of the Manta Ray Queen. She went behind her mother's back to help the squiddles and loved to sing while no one was watching.
- Chumcrumpet (blood orange) is a comic relife character though his ratings were incredibly low. Everytime anyone tried to talk to him it became clear that the only thing he could say was "Uhmnumnumnumnumfrummmmmpblubbbcaboooooowwwwwarrrrkit" and "no". It was due to a tramatic accident he faced as a child. He was present only in season three, but has been announced to be in the Squiddles live-action movie coming in 2018.
- Frostyfoam is a female squiddle who was featured in season two episode six, The Little Squidlette. She desperately wanted to live a human life and left the other squiddles, but was taught by the main cast that she should love and embrace who she is.
- Seaweed (Sea Unicorn) made a little appearance in Season two. She was given to Plumthroat as a foal, but in the season finale she left to search for her parents