I'm glad to hear it went well with the presentation.
The idea of giving your characters some more destinguishable fish/sea creature feature is not bad. I think it's easyer to change it more alien-like after you have the base than start into the wild with no boundaries...
The head designs you have for the female and male are really cool-the larger ones. I like how you managed to add that collar to them, it looks natural/believable. But since this is game design, you could experiment with the shape a bit more (maybe making it more spiky), to make it as clear as possible that it is dangerous to be round that one when the collar is spreaded.
I know you are not focusing on rendering the image but it would be easyer to read the image if it wasn't as bright, if you would use darker values too.
Anyways, it's cool to see your characters go through all sorts of metamorphosis and fashion styles:)