Good tank mates for Zebra Danio? 10 gallon tank with heater and filter, currently cycling with BioSpira…?
I currently have a 10 gallon fish tank with four Zebra Danio; it’s been cycling with BioSpira for a day now and water levels are looking good. Fish are lively and healthy, and I’m wondering what fish to get and companions for them when the cycle is over.
So far I’m pretty decided that I want two Panda Cory in addition to the danio.
If I do get more fish, how many fish do you suggest I add at the time — also, do I need to add BioSpira when introducing new fish? I used 10 ML for the 10 gallon tank. Do you think I could add a few cardinal tetra and/or a peaceful (well, TOLERANT) male betta fish? If so, how many? Yes, I know that if I did add the betta fish it would only be one. 
I’m referring to the tetra or other fish.
If not, what stocking suggestions do you guys have for this tank?
I wouldn’t put more than 6-7 fish in a 10 gallon tank. Not only will it keep you from having to do frequent water changes, but you don’t want to over crowd them. 1 male Betta would be alright, maybe Platties or Mollies would be good. You shouldn’t have to add any more BioSpira, since it is already been added.
I think you should add 4 panda cories and 1 siamese fighting fish. Panda cories do better when there are many of them. Many people say 6 is best, I agree but I have only three happy healthy cories. For your tank the least number of cories you can add is four, even after that it’s already overstocked, but there’s nothing a little extra filtration and maintenance can solve. You should add the cories all at once because they love the company of each other, then after a week, you can add the male betta. It’s better to add the most aggressive last so that the other inhabitants will not get overstressed with the aggression. But do not worry because male bettas are only at their most aggressive with guppies, angelfish and other bettas. They don’t mind not harmful at all cories and super quick moving danios. I think your tank will become just gorgeous with these fish.
Here is a website that tells some of the fish that will be compatible with danios and other fish http://www.petco.com/assets/livefish/freshwaterchart.html
As far as how many fish you can have, the general rule is 1 gallon of water for every inch of full-grown fish. You want to introduce new fish to the tank gradually, so float the bag or container from the pet store in your tank for about 20 minutes and add some of the water from your tank to the container or bag. Also, don’t introduce to many fish to the tank at once as this will cause the ammonia level to spike to much and can harm the fish. I suggest 2 and wait a few days before adding more. You shouldn’t have to add more of the treatment unless the bottle says to. If you put tetras and bettas together, make sure the tetras do not nip at the betta’s fins. If they do, you must separate them.