Hello everyone, I'd love to introduce myself but my fish might be in trouble so here's the problem:

20 gallon tank, 3 calico ranchus ( flame me for overstocking later ok),
the smallest eheim ecco filter and one eheim aquaball.

Two weeks old tank, artificial plants and driftwood deco. One fish started spawing Monday, but only during afternoons. Water goes all milky for a while but clears overnight.

Spawning fish acts normally during the day but after spawning acts half dead! Also, she has taken to hiding behind the aquaball filter - at first i thought the suction's pulling her in but I've seen her swim out by herself?? It looks kinda awful cause she seems stuck between the filter and the glass

All 3 eat as much as ever.

Do not intend to keep the eggs, most get eaten (well, all actually) so is there anything i can do to help? How long is spawning season anyways?

Help!

Well, the spawning season is usually in spring, and somewhat in fall, but spawning can be triggered by a few other things - a bigger water change, temperature fluctations, introducing a new fish (mostly female), higher protein food for a time,.....
Is your female being chased around by any of the other 2 fish? If so, you would have to separate the female from them. Males can chase a female to death, especially if the fish is smaller of weak already. If you don't have another tank to put her in, I bought some cheap plastic containers with loads of holes in the dollar store, they float. You can put the female in there, she is separated then, but still benefits from the tank's filtration, since the holes allow circulation.
If she isn't being chased, I would just give her rest and quiet, turn the lights off more, and good food. It takes quite a toll out of the females sometimes, and they need to recuparate from it.....
Post back how she is doing....

Well, she seems ok today! Thanks!

That is very good news indeed!!