Hi KeyOh, and welcome to the forum!
Editing the aquarium won't be possible due to too much work needed to make everything fit together. Also Jim (who wrote the program), says the plastic toys will apear in the freshwater aquarium, but not likely in the marine one.
After the completion of the Freshwater Aquarium, Jim will resume work on the true 3D background of the marine aquarium. When it is completed, collision detection will be much easier to control which will allow for more freedom when it comes to swimming. Different swimming speed and techniques will be implemented eventually.
Fish mating sounds a bit intricate. The only approach that would satify Jim would be a realistic one. Sounds a bit complex if you ask me.
Fish eating their young might be fun at
www.reallydangerpets.com but not really fitting for serenescreen.com, wouldn't you agree?
Fish fighting doesn't sound serene either.
Fish feeding has gotten a thumbs up. – But after the freshwater tank and the 3D background.
I'm not really interested in seeing fish excrement enough to second your wish for it. Sorry.
Individual behaviour has a green light – it will come along with the swimming speed issue above.
Looking through the glass? You mean instead of closing their eyes as they do right now?
Why would you want dirt/algae?
Inserting your own background won't happen. press "w" and notice how the current 2D background is intricately matched to all those white lines allowing the fish to swim behind as well as in front of the coral? How would you fix that on a custom background? Also the static 2D background will be replaced with a true 3D one which makes the point moot.
Water effects. I agree. And some modern light effects would be cool as well.
That fish wouldn't fit very well with the marine tank as it is a freshwater species. It is being considered for the freshwater tank though. After the 3D background, Jim has said he will create a few creature packs with some special creatures sold separately. Among those will most certainly be a banded coral shrimp which might be the closest thing you'll get to a "tank cleaner".
/Tiny List