These were created using Adobe Flash. I want to write Macromedia there, but this was well past the naughties! Several were tied into the 'BADASS' Universe and in fact you can see them pop up in a very old comic page somewhere on this site, as well as in movies made in Cinema4D in 2003 or thereabouts.
The final appearance for several of the fishes is in the 'TURBINEhead' Android game, which may still be available on the Android Play store depending on my tax status (it varies seasonally). TURBINEhead will have a continued development at one point, and the fishes will be there!